Onana, who is expected to join Inter at the end of the season on a free transfer, was travelling from the capital Yaounde to the port city of Douala, where the Indomitable Lions are gathering ahead of their World Cup play-off against Algeria.
Local media showed pictures of the car in which Onana was travelling, and another vehicle, with the front part of each being badly mangled.
Onana, 25, was taken from the crash site to the Cameroon team base and posed for pictures, appearing unhurt; however, it was determined he should head for hospital check-ups.
"Andre Onana is fine," the team's official Twitter page stated. "The Indomitable Lions goalkeeper joined his team-mates in the den in Douala this morning.
"More fear than harm for the moment after the traffic accident he suffered early this morning in Sombo on the Yaounde to Douala axis.
"Andre Onana will undergo in-depth examinations in a referral hospital centre in Douala."
Cameroon will host Algeria in the first leg of their play-off on Friday, with the second leg taking place in Blida next Tuesday. The aggregate winner will qualify for the Qatar 2022 finals.
Bafana Bafana required a point from the game in Cape Coast to reach the final round of CAF qualifying for the 2022 World Cup, but fell to a 33rd-minute Andrew Ayew penalty.
Ghana advanced to the next stage at South Africa's expense by finishing above their opponents in Group G on goals scored, with the teams level on both points and goal difference.
However, South Africa Football Association (SAFA) chief executive Tebogo Motlanthe felt a number of calls – including the penalty incident – went against his side.
"The match officials have decided the game, which is not what is supposed to happen," Motlanthe said in a statement posted on the SAFA's official Twitter page on Monday.
"We will be writing to both CAF and FIFA – firstly to investigate how the game was handled and secondly to challenge some of these decisions.
"We have already registered with the match commissioner that we will be making a formal complaint."
Ghana's decisive penalty was awarded by referee Maguette Ndiaye for Rushine de Reuck's challenge on Daniel Amartey.
"We are very disheartened by their actions and we can't let it destroy the players – when we have the chance to challenge, we will challenge," Motlanthe said.
"We feel very much robbed because it is not an isolated incident of a penalty.
"There are just a lot of questionable decisions by match officials and we will get an expert to dissect other incidents, so we can make a strong case."
South Africa are no strangers to having to replay a game, with their 2-1 win over Senegal in 2018 World Cup qualifying being wiped out after a referee was found guilty of manipulating the match.
Motlanthe added: "Of course we are looking at the precedent whereby FIFA ordered us to replay Senegal and we think that if justice needs to be served the same decision should be taken against this Ghana game."
However, Ghana match-winner Ayew does not believe South Africa have a case, arguing his side were themselves hard done by.
"It was a clear penalty on [Amartey]. In fact, we had chances to get more penalties and should have been given two more," he told reporters after the match.
DR Congo, Egypt, Mali, Morocco and Senegal are also through to round three of qualifying, with four more teams left to join them.
