Naomi Osaka would be prepared to spend another two weeks in quarantine to be able to play at a "very special" Olympics in Tokyo.

Postponed due to the coronavirus pandemic, the Games are scheduled to begin on July 23 this year.

This year's Australian Open will begin on February 8 after players quarantined ahead of the first grand slam of the year.

Osaka said she would be prepared to do it all again if it meant she got the chance to play at the Olympics.

"Honestly, my concern isn't the athletes. The way that I feel is I will stay in my room for two weeks to play the Olympics. I missed out on the last one," the Japanese star told a news conference on Sunday.

"Playing in Tokyo would be very special to me. My concern would be the general safety of everyone else because you're opening the country.  Everyone is flying in from different places. I would just want the public to feel safe.

"I feel like the athletes definitely would want to play, but I would want the public to feel safe."

Doubts have also been cast over the Olympics going ahead this year due to COVID-19.

Osaka, a three-time major champion, said while people she had spoken to were excited, some were worried.

"For me the people that I've spoken to, they're really excited about it, but they're concerned because, I don't know, there's just like so many different people entering. I don't know," she said.

"For the people I've talked to, they said as long as everyone is safe, as long as Japan is getting better and not worse, then it should be okay.

"But for me, hmm, don't quote me on that."

Ahead of the Australian Open, Osaka is playing the Gippsland Trophy, where she will face either Alize Cornet or Ajla Tomljanovic in the second round.

The Australian Open is set to welcome up to 30,000 spectators each day when the tournament begins on February 8 in Melbourne.

Local officials have given the go-ahead for fans to head to Melbourne Park, predicting a near-normal atmosphere when action begins at the year's first grand slam.

Last year's US Open was contested behind closed doors in New York, while only 1,000 paying fans were allowed at Roland Garros on each day of the 2020 French Open.

However, the COVID-19 crisis has been tightly managed in Australia, to the point where it was reported on Saturday that there had been no new local cases in the state of Victoria for 24 days.

The crowds will be split between day and evening sessions, and the number of fans allowed will drop to 25,000 for the final six days of the tournament, when fewer courts will be in operation.

Saturday's announcement means the event will be capped at around 50 per cent of capacity.

Tournament director and Tennis Australia chief executive officer Craig Tiley said it had taken "a massive team effort" to accommodate the arrival of around 1,000 players and officials into the country, with all required to spend two weeks in quarantine.

Victoria sports minister Martin Pakula said on Sky News Australia: "On Rod Laver Arena, as we get towards the end of the tournament, we'll have an incredible atmosphere – not that different to the atmosphere we've seen in all the Opens in the years past.

"That's really a testament to the work Victorians have done to get our numbers to zero but also the extraordinary work that Craig and the team at Tennis Australia has done."

Serena Williams and Rafael Nadal agreed it was great to be playing in front of busy grandstands again as tennis stars emerged from lockdown in Australia.

The women's and men's tennis tours have been contested largely behind closed doors over the past year, and a number of tournaments, most notably Wimbledon, have been cancelled due to the COVID-19 crisis.

The Australia public has given a cautious welcome to the arrival of the world's leading players, who have been quarantining in hotel rooms for much of the past fortnight, only allowed to briefly leave in order to train.

Ahead of the Australian Open, which begins on February 8 in Melbourne, Williams and Nadal are among a star-studded set of players who travelled to Adelaide to feature in the 'A Day at the Drive' exhibition event.

They both scored victories on Friday, with Williams defeating US Open champion Naomi Osaka 6-2 2-6 10-7 and Nadal snatching a 7-5 6-4 win over Dominic Thiem.

The delight in both at seeing crowds at a tournament was plain, with Williams saying in an on-court interview: "Thanks everyone for having us. We haven't played in front of a crowd in over a year. It's been a really long time."

In fact, it has not quite been a full year since the tours locked down initially, as it was early March when most tournaments began to be called off, with crowds frozen out.

Williams said the reception made the difficult past fortnight, being hidden away from the world, worth the strain for the players.

"This is really cool and then for having us and trusting us with your laws was great," said the 23-time grand slam winner. "We were so excited to be here and it's worth it."

Nadal said he was "super happy" to still be playing at the highest level and back in front of Australian crowds.

The pandemic has been carefully managed to the point where very few have the virus and it is considered safe to allow crowds into sporting events in the country.

Nadal said: "Hopefully this situation will go away quick and we will be able to enjoy fans on court [around the world].

"We're super excited to have fans at the Australian Open and today."

That optimism and excitement was shared by men's world number one Novak Djokovic, who played just one set against Jannik Sinner due to a problem with blisters on his right hand.

Eight-time Australian Open champion Djokovic told fans: "Thank you so much for coming out and making our day and making our year.

"We didn't play in front of this much crowd for 12 months. This is definitely something very special.

"It wasn't easy, obviously, with 14 days being constrained in the room and a few hours to train, but at the end of the day it was worth it because you guys made it very special today for us."

Novak Djokovic apologised but confirmed he had been dealing with a blister after only playing a set of his exhibition match in Adelaide.

The world number one had reportedly withdrawn and was replaced by Filip Krajinovic for a clash against Jannik Sinner.

But Djokovic played the second set, winning it 6-3 after Krajinovic had taken the opener 6-3 on Friday.

The 17-time grand slam champion, who had a blister on his right hand, apologised after the match.

"I'm sorry that I didn't step in on the court from the beginning," Djokovic told Channel 9.

"I had to do some treatment with my physio and wasn't feeling my best the last couple of days, I didn't know how I'm going to react.

"I wanted to play and I wanted to get out here and hopefully it was enough for you guys to see all three of us performing in front of you on the court today, I hope you enjoyed."

Djokovic, who came out of hotel quarantine on Friday, said he could not pass up the opportunity to play in front of fans.

"It's not easy but it's part of what we do. We are professional athletes we learn over the years to play with the pain and it's just a question and case whether that pain is bearable or not," he said.

"Obviously coming off from the hard training block and having an ATP Cup and Australian Open around the corner you don't want to risk it too much.

"But the emotion was so strong in me to come out on the court today seeing almost full stands, I had to play, that's it, I had to play."

Djokovic is due to play the ATP Cup starting on Tuesday, before the Australian Open begins on February 8.

Andy Murray has withdrawn from the Australian Open a little over a week after testing positive for coronavirus.

Murray, a five-time finalist in Melbourne, went into isolation at home after returning a positive test on January 14.

The three-time major winner, ranked 123rd in the world, had hoped to compete at the first grand slam of the year after being granted a wildcard.

However, tournament organisers indicated it would be difficult for Murray to remain in the draw as he would be unable to travel via one of the official charter flights containing other players before going through the required period of quarantine.

On Friday, the 33-year-old confirmed he had been unable to come to a "workable" solution with authorities.

In a statement carried by The Guardian and other UK media outlets, Murray said: "Gutted to share that I won't be flying out to Australia to compete at the Australian Open.

"We've been in constant dialogue with Tennis Australia to try and find a solution but we couldn't make it work.

"I want to thank everyone there for their efforts, I'm devastated not to be playing out in Australia. It's a country and tournament that I love."

The build-up to this year's Australian Open has been impacted by players having to spend a two-week quarantine in their hotel accommodation.

A total of 72 competitors have been unable to leave their rooms after positive coronavirus tests among passengers on the chartered flights to Melbourne.

Players have been unable to access practice courts and many have complained on social media about sub-standard food and conditions, with Yulia Putintseva, the world number 28, sharing videos showing mice in her room.

The tournament is due to start on February 8.

Tennis umpire Carlos Bernardes is "recovering well" after reportedly suffering a heart attack ahead of the Australian Open.

The veteran Brazilian, who has officiated in US Open and Wimbledon men's singles finals, was taken from his hotel to a Melbourne hospital on Wednesday after falling ill.

It was widely reported he had a heart attack, with Bernardes pictured on a stretcher while being loaded into an ambulance.

The ATP, which runs the men's tour and has been Bernardes' employer since 1990, offered an positive update on Thursday.

In a statement, the governing body said: "Following admittance to hospital [non-COVID related] on Wednesday in Melbourne, we are pleased to report that ATP umpire Carlos Bernardes is recovering well.

"Carlos passes on his gratitude for all the well wishes he's received, and we wish him all the best for a full recovery."

According to Brazilian tennis website TenisNews, Bernardes remains under observation but is expected to leave hospital on Saturday.

He was staying at The View, one of three hotels where Australian Open players and tennis officials are quarantining for two weeks after their arrival in the country.

Novak Djokovic has denied he was being "selfish, difficult and ungrateful" in making suggestions for easing quarantine restrictions ahead of the Australian Open.

Djokovic came in for criticism after it emerged he had sent Australian Open tournament director Craig Tiley a list of potential ways for lockdown conditions to be improved for players who are under a strict lockdown in Melbourne.

Less than three weeks before the first major of the year gets under way, 72 players are consigned to their hotel rooms due to positive coronavirus tests on their flights to Melbourne.

World number one Djokovic does not have to adhere to such stringent rules in Adelaide, as he arrived on a virus-free flight.

The 17-time grand slam champion was labelled a "tool" by Nick Kyrgios after he was said to have asked for less time in isolation for players, requested they are given private housing with access to training courts, and better food.

Djokovic responded on Wednesday by stating that he was only trying to look out for his fellow players and expressed his gratitude to tournament organisers, the Australian government and the people of Melbourne.

He posted on social media: "My good intentions for my fellow competitors in Melbourne have been misconstrued as being selfish, difficult and ungrateful. This couldn't be farther from the truth

"I genuinely care about my fellow players and I also understand very well how the world is run and who gets bigger and better and why.

"I've earned my privileges the hard way and for that reason it is very difficult for me to be a mere onlooker knowing how much every help, gesture and good word mattered to me when I was small and insignificant in the world pecking order.

"Hence I use my position of privilege to be of service as much as I can where and when needed."

The Serb added of his correspondence with Tiley: "In our email exchange I used an opportunity to brainstorm about potential improvements that could be made to the quarantine of players in Melbourne that were in full lockdown.

"There were a few suggestions and ideas that I gathered from other players from our chat group and there was no harm intended to try and help.

"I was aware that the chances were low that any of our suggestions would be accepted, just like my request to quarantine with my team in Melbourne instead of Adelaide was denied prior to our travel because of the strict government regulations.

"I understand that organising international sporting events during a pandemic poses health risks to the local community and to the players themselves.

"Therefore, I would like to express my full gratitude to Tennis Australia, the Australian Government and local citizens for being willing to take this risk with us for the love of the game and the multiple opportunities it brings to the economy of the country and its people.

"We are honoured and we will all do our best to follow the guidelines and protocols put in place. We do hope that we will be able to nurture our bodies and be ready for the mental and physical endurance and strength tests that are ahead of us once the competition starts.

"Things in the media escalated and there was a general impression that the players [including myself] are ungrateful, weak and selfish because of their unpleasant feelings in quarantine. I am very sorry that it has come that because I do know how grateful many are.

"We all came to Australia to compete. Not being able to train and prepare before the tournament starts is really not easy. None of us ever questioned 14 days of quarantine despite what is being said by media outlets."

Victoria Azarenka called for greater understanding from players stuck in hotel quarantine ahead of the Australian Open.

After being exposed to coronavirus on flights, 72 players – including Azarenka – have been forced into a two-week quarantine ahead of the tournament beginning on February 8.

Novak Djokovic reportedly made several requests, which were rejected, of officials for players in quarantine, while Roberto Bautista Agut compared the conditions to prison.

But amid complaints on social media, two-time Australian Open champion Azarenka pleaded for players to be more understanding in a measured statement.

"Dear players, coaches, entourage and Australian community. I would like to take a moment and address some of my colleagues as well as the media around the world," the Belarusian wrote on Twitter.

"This has been a very difficult time for a lot of us that did not expect to end up in the situation we are in today, myself included. To be in a 14-day hard quarantine is very tough to accept in terms of all the work that everyone has been putting in during their off-season – to be prepared for playing our first grand slam of the year. I understand all the frustration and feeling of unfairness that has been coming and it is overwhelming.

"We have a global pandemic, nobody has a clear playbook of how to operate at full capacity and without a glitch, we all have seen it last year. Sometimes things happen and we need to accept, adapt and keep moving.

"I would like to ask all my colleagues for cooperation, understanding and empathy for the local community that has been going through a lot of very demanding restrictions that they did not choose, but were forced to follow.

"I would like to ask to be sensitive as well to the people who have lost their jobs and loved ones during this horrible time for all of us around the world. I would like to ask all of us to have respect for people who work tirelessly to try to make our lives easier.

"I would like to ask the media to please have consciousness on the impact and influence you bring to this situation and to the community. I would like for the people in the community to know and understand that we have it as our top priority to ensure the health [and] safety of all the people.

"Lastly, I would like for us to please try to support each other as much as someone can or is willing to. Things are always easier when you have a compassionate environment and work together."

Victoria endured tough restrictions after a second coronavirus wave last year.

On Tuesday, the state recorded its 13th consecutive day of no locally acquired cases of COVID-19.

Roberto Bautista Agut labelled the quarantining of players ahead of the Australian Open a "complete disaster", comparing it to prison.

After being exposed to coronavirus on flights to Australia, 72 players are in hotel quarantine for two weeks ahead of the tournament starting on February 8.

Players have hit out at the conditions, although tournament director Craig Tiley insisted on Tuesday most were happy to be in Australia.

But world number 13 Bautista Agut slammed the position players had been put in.

Told he looked like he was in prison, the Spaniard told Sport5: "It's the same, it's the same, with Wi-Fi.

"These people have no idea about tennis, about practice courts, has no idea about anything, so it's a complete disaster because of that, because the control of everything.

"It's not Tennis Australia, it's the people from the government."

Victoria on Tuesday recorded its 13th consecutive day of no locally acquired coronavirus cases, with three of the four in hotel quarantine linked to the Australian Open.

Bautista Agut, a 2019 quarter-finalist at Melbourne Park, said two weeks in quarantine would be difficult.

"I did work in the room but it's not the same," he said.

"I was feeling very, very tight and I cannot imagine staying two weeks like this. It's really, really tough."

Australian Open tournament director Craig Tiley defended Novak Djokovic, saying the world number one had provided "suggestions", not demands.

With 72 players forced into quarantine for two weeks after being exposed to coronavirus on flights, Djokovic reportedly made demands regarding their conditions.

Among them, the eight-time Australian Open champion reportedly asked for players to be moved to private houses with tennis courts, with his requests rejected.

But Tiley played down the reports, saying Djokovic had simply made suggestions.

"Novak wrote a note, these weren't demands, these were suggestions," he told Channel 9 on Tuesday.

"But he too is understanding what two weeks of lockdown means."

Tiley also backed the players despite reports and social media posts suggesting they were unhappy about being forced into quarantine.

"Last night we spent quite a bit of time with the playing group going through a number of different items because they've just been here for a few days getting used to this quarantine environment," he said.

"I have to say on that call there were about 500 players and the vast majority are happy to be here, pleased to be here and really getting ready in the next two weeks to be able to get out and play in the lead-in events and then play the Australian Open on February 8.

"I think the reports we're reading and the things we're seeing doesn't represent the entire playing group. For the most part, they've been pretty good."

With the preparations of 72 players so far impacted by quarantine, there have been suggestions the Australian Open be changed to a best-of-three sets format in the men's draw.

But Tiley said he had no plans to make such a drastic change.

"We're a grand slam at the end of the day and right now three out of five sets for the men and two out of three sets for the women is the position we plan on sticking to, starting February 8," he said.

Nick Kyrgios has labelled Novak Djokovic "a tool" after the world number one reportedly issued a list of demands for players under strict quarantine conditions ahead of the Australian Open.

Defending women's singles champion Sofia Kenin is among 72 players who are consigned to their hotel rooms due to positive coronavirus tests on flights they took to head out for the first grand slam of the year.

Players have posted social media clips of them training and in their rooms, with some complaining about the conditions they are having to contend with for 14 days.

Bernard Tomic's girlfriend, Vanessa Sierra, expressed her grievances over the standard of food and having to wash her own hair and dishes during her period of quarantine with the world number 228 so far.

Djokovic does not have to adhere to such strict rules in Adelaide, where he is due to play in an exhibition tournament before the Melbourne major, as he arrived on a virus-free flight.

Yet the 17-time grand slam champion is said to have asked for less time in isolation for players, requested they are given private housing with access to training courts, and better food.

Kyrgios tweeted on Monday: "Djokovic is a tool. I don't mind Bernie [Tomic] but his Mrs obviously has no perspective, ridiculous scenes Man."

Three weeks before the Australian Open is due to get underway, Victorian premier Daniel Andrews said the players will not be getting any "special treatment."

He said: "The virus doesn't treat you specially, so neither do we.

"I know there's been a bit of chatter from a number of players about the rules.

"The rules apply to them as they apply to everybody else and they were all briefed on that before they came and that was the condition on which they came. So, there's no special treatment here."

A further 25 players have been forced into hard lockdown for two weeks prior to the Australian Open, tournament organisers have confirmed.

Tennis' season-opening grand slam was plunged into crisis on Saturday when it was announced 47 players would be consigned to their hotel rooms for 14 days and not eligible to practise.

Officials said the protocols were as a result of two passengers testing positive for coronavirus on a flight from Los Angeles that arrived on Friday morning, along with another passenger who flew in from Abu Dhabi.

That affected 24 players aboard the LA flight and 23 on the plane from Abu Dhabi, while another positive test for a passenger arriving in Melbourne from Doha on Saturday morning has taken the total number of players affected to 72.

A statement from the Australian Open read: "One positive COVID-19 test has been returned from a passenger on a charter flight into Melbourne from Doha which arrived at 5.30am on January 16.

"The passenger is not a member of the playing contingent and had tested negative before the flight.

"There were 58 passengers on the flight, including 25 players. All are already in quarantine hotels.

"The 25 players on the flight will not be able to leave their hotel room for 14 days and until they are medically cleared. They will not be eligible to practise."

About 1,200 players and staff have been arriving in Melbourne on sparsely populated aeroplanes ahead of the delayed Australian Open, which is due to get under way on February 8.

Speaking on Saturday, Tennis Australia CEO Craig Tiley insisted the tournament would be going ahead despite the chaos and the lack of preparation time for many of the playing contingent.

"It's not something we wanted to happen," he told The Today Show. "We were hoping every flight would be okay. We're in this situation, we have to deal with it.

"The Australian Open is going ahead and we'll continue to do the best we can possibly do to ensure those players, who are not in a great position, find it somewhat acceptable.

"We're planning on February 8, we do have that buffer time in there. We're looking forward to welcoming fans to the Australian Open.

"Ticket sales have been going well, we've got two weeks of great tennis and our intention is to continue with those dates."

The Australian Open will go ahead as scheduled despite 47 players being forced into hard lockdown amid positive COVID-19 cases, according to Tennis Australia's CEO Craig Tiley.

The tournament was plunged into a crisis on Saturday when two positive cases were detected on two charter flights carrying players into Melbourne.

Tournament officials said two passengers on a flight from Los Angeles that arrived on Friday morning had tested positive, along with one passenger who travelled in from Abu Dhabi.

None of those who tested positive were said to be players, although one was described as a "participant", which may mean a member of a player's entourage.

Australia's Department of Health and Human Services (DHHS) said those aboard the flights were considered 'close contacts' of those with the virus, and that means they will be confined to their hotel bedrooms for the next two weeks.

Isolating players are unable to leave their hotel rooms for 14 days until they are medically cleared, but Tiley insists there are no plans to postpone the tournament. 

"It's not something we wanted to happen," he told The Today Show. "We were hoping every flight would be okay. We're in this situation, we have to deal with it.

"The Australian Open is going ahead and we'll continue to do the best we can possibly do to ensure those players, who are not in a great position, find it somewhat acceptable.

"We're planning on February 8, we do have that buffer time in there. We're looking forward to welcoming fans to the Australian Open.

"Ticket sales have been going well, we've got two weeks of great tennis and our intention is to continue with those dates."

The Australian Open has pulled out all the stops in an effort to get the grand slam on, and that has meant all players have had to arrive early and go into quarantine, although most will be allowed to spend five hours outside their hotel rooms each day, to allow for practice and gym work.

Such limited liberties will not be afforded to those hit by the news of the positive tests on their flights.

The Australian Open was plunged into a crisis on Saturday as positive COVID-19 cases were detected on two charter flights into Melbourne, forcing 47 players into hard lockdown for a fortnight.

Tournament officials said two passengers on a flight from Los Angeles that arrived on Friday morning had tested positive, along with one passenger who travelled in from Abu Dhabi.

None of those who tested positive were said to be players, although one was described as a "participant", which may mean a member of a player's entourage.

About 1,200 players and staff are arriving in Melbourne ahead of the delayed Australian Open, which is due to get under way on February 8.

They are travelling on sparsely populated aeroplanes to allow for social distancing, with 79 people, including 24 players, aboard the flight from Los Angeles and 64 people, including 23 players, arriving from Abu Dhabi. It was reported that players affected included recent grand slam champions.

A statement from the Australian Open said the players "will not be able to leave their hotel room for 14 days and until they are medically cleared. They will not be eligible to practise."

Australia's Department of Health and Human Services (DHHS) said those aboard the flights were considered 'close contacts' of those with the virus, and that means they will be confined to their hotel bedrooms for the next two weeks.

The Australian Open has pulled out all the stops in an effort to get the grand slam on, and that has meant all players have had to arrive early and go into quarantine, although most will be allowed to spend five hours outside their hotel rooms each day, to allow for practice and gym work.

Such limited liberties will not be afforded to those hit by the news of the positive tests on their flights.

French player Alize Cornet questioned why such steps were necessary, writing on Twitter: "Soon, half of the players from the AO will actually have to isolate. Weeks and weeks of practice and hard work going to waste for one person positive to Covid in a 3/4 empty plane. Sorry but this is insane."

The 30-year-old world number 53 added: "I just think that these measures are not made to hold an international tennis event."

Cornet, who said she was not on an affected flight, believed there were meant to be measures in place to avoid wholesale lockdown in the case of positive tests.

She said: "We've been told that the plane would be separated by section of 10 people and that if one person of your section was positive, then you had to isolate. Not that the whole plane had to."

Victoria on Saturday recorded its 10th consecutive day with no locally acquired cases of coronavirus.

Madison Keys is set to miss the Australian Open after testing positive for coronavirus.

The 2017 US Open runner-up announced on Thursday that she contracted COVID-19 before she was due to fly out for the first grand slam of the year.

Keys did not state she will definitely miss the major, which starts on February 8, but it appears the American will not make the trip to Melbourne.

The American wrote on Instagram: "Hi everyone, I wanted to let you know that I unfortunately tested positive for COVID-19 before I was supposed to fly to Australia.

"I'm very disappointed to not be able to play in the coming weeks after training hard in the off-season and knowing Tennis Australia and the tours did so much to make these events happen.

"I am self-isolating at home and will continue to follow all the necessary health precautions. I look forward to being back on tour next month."

It was revealed earlier in the day that three-time major winner Andy Murray has also tested positive for the virus, but still hopes to play in the Australian Open.

Meanwhile, world number 50 Tennys Sandgren was cleared to board a flight from the United States bound for Melbourne despite revealing he returned a new positive coronavirus test this week. 

The American, twice a quarter-finalist at Melbourne Park, initially posted to social media on Wednesday that he had tested positive for the virus for a second time. 

Although his first instance of having the illness was recorded in November, the 29-year-old's participation in the tournament appeared to be in doubt. 

But as he continued to update followers through the day, it emerged he had been allowed to board his flight. 

Players will only be allowed into Australia with proof of a negative test just prior to departure, or with approval to travel as a recovered case at the complete discretion of an Australian government authority.

Anyone wanting to travel out for the tournament who previously tested positive is required to provide additional and highly detailed medical information as proof they are a recovered case and no longer infectious or a risk to the community.