A police officer has been charged with robbing and bashing a cab driver in Sydney's eastern suburbs.

The 23-year-old off-duty constable from Central Metropolitan Region police station allegedly jumped in the cab on Bayswater Road, Kings Cross about 2am on Saturday.

During the ride he is said to have got into an argument with the male driver, who pulled over in Todman Avenue, Randwick.

"After allegedly assaulting the cab driver and stealing a number of items from the cab the 23-year-old man ran from the scene," a police statement said.

The constable was arrested at 5.30pm on Saturday and charged with assault and robbery.

He was given bail and is due to appear at Downing Centre Local Court on June 28.

AAP