Police have arrested a man on a charge of raping a Ukrainian woman at Koh Samui's Thongson beach early last week.

Police said Nathapong, 27, was detained outside a convenience store in Bo Phut on Koh Samui on Sunday. They also seized the motorcycle he used on the day of the alleged crime. The suspect's full name was not given.

Bo Phut police said a 32-year-old Ukrainian tourist said she was raped on Thongson beach about 9am on July 8.

Police showed her security camera footage of the suspect, and she identified him as her attacker.

The suspect, who is from Prachuap Khiri Khan province, allegedly admitted he was the suspect in the arrest warrant issued on Sunday, but claimed the woman had give her consent for the act.

The investigation was continuing.