A 17-year-old girl has filed a complaint with Muang Khon Kaen police in the northeastern province of Khon Kaen, accusing Somluck Kamsing of sexual assault.

Police were expected to issue a summons for the former Olympics boxing gold medallist to acknowledge the charge.

Mr Somluck, 50, on Monday insisted he is innocent. Exasperated, he said once the case was settled he would move to live in France.

The girl, whose name was withheld, is from Nong Kung Si district of Kalasin province. She told police when she filed her complaint on Sunday that she met Mr Somluck at a pub in Muang district, Khon Kaen province, on Saturday night.

The former boxer took her to a hotel room about 3.30am on Sunday. There, she was sexually assaulted by Mr Somluck, she alleged.

Contacted by reporters, Mr Somluck said he had been informed of the complaint and had hired a lawyer to contest the charge.

Interviewed on TV Channel 8, he said while in the pub he was befriended by the girl, who asked for a selfie photograph with him. He later took her to the hotel. Mr Somluck said they had both taken off their clothes. Before going further, he had asked how old she was. When the girl replied she was 17, he stopped making advances and fell asleep.

Mr Somluck said he did not go any further than that and was certain of his innocence.

Mr Somluck told the Bangkok Post on Monday that he would remain in Khon Kaen, his home province, until the case is over, and then move overseas.

"After the case is over, I will go and live in France. I am tired of this kind of social affair. I insist I did not rape or hurt her. I have not yet received a police summons, but I am ready for it and will fully cooperate with the police," he said.