A Japanese athlete at the Asian Games has been charged by police after admitting to stealing a camera from a South Korean journalist, police said on Saturday.

The Japanese Olympic Committee said in a statement the athlete was swimmer Naoya Tomita, a gold medallist from Guangzhou in 2010 but who finished out of the medals in Incheon.

Incheon police told Reuters the athlete had been booked without detention and barred from leaving the country.

"After we received a report, we analysed CCTV and could see that it was a Japanese athlete, but to confirm it we went to see the Japanese team leader and showed him the clip," police told Reuters by telephone.

Police located the athlete cheering on his team mates at a venue and spoke to him in a private interview.

"He admitted it right away," police said. "The case will be dealt by the prosecutor's office next week."

An Asian Games official said the Japanese delegation would expel Tomita from the team and planned to send him home immediately.

The swimming events the Asian Games wrapped up on Friday.