An off-duty police officer, who was suspected of being in a scam farm in Cambodia, has returned home and resigned from the force, Police Commissioner Joe Chow said on Saturday.

Speaking after a passing-out parade, Chow said a team of four officers had been dispatched to Cambodia to better understand the situation and facilitate the officer's return.

"He returned to Hong Kong on Thursday, and our personnel also returned on the same day," he said.

"He submitted his resignation letter. The case is still under investigation, and the details are not yet available for disclosure."

The case has been handed over to the Organised Crime and Triad Bureau for further investigation.

Chow also said the force is fully prepared for the upcoming National Games, which Hong Kong is co-hosting with Guangdong and Macau.

With the event starting in two months' time, he said security and crowd management plans are in place to ensure the Games proceed smoothly and safely.