Nick Kyrgios accused Australia co-captain Lleyton Hewitt of throwing him "under the bus" following his decision to withdraw from the United Cup.

The 2022 Wimbledon finalist, who has been struggling with an ankle injury, was due to line up alongside the likes of Alex De Minaur and Jason Kubler in the inaugural edition of the team event.

However, Kyrgios surprised team-mates with his decision to pull out of the event, with the 27-year-old switching his focus to achieving full fitness for next month's Australian Open.

Hewitt was unaware of Kyrgios' withdrawal until his public announcement and said he needs to improve his communication skills.  

Kyrgios' withdrawal was followed by that of Ajla Tomljanovic, who pulled out of her match against Great Britain's Harriet Dart due to a knee injury.

Kyrgios responded to a Twitter post about the news, questioning whether co-captain Sam Stosur would respond the same way Hewitt did.

"Mmm I wonder if Stosur will throw her under the bus like our captain did for me... 'hard to prepare when you don't know what's going on'," Kyrgios wrote.

Australia suffered a 3-2 defeat to Great Britain in their Group D meeting, although they will have another chance to progress to the knockout stage when they face Spain next week.