A couple from Poland arrested for public nudity on Koh Phangan have told police they were just expressing their love.

Local residents spotted the pair locked in a naked embrace on Ban Tai Road on the tourist island at 4.30pm on Monday, police said.

Police went to the scene, photographed the couple and told the 27-year-old man and the 24-year-old woman to get dressed before arresting them.

Police quoted the couple as saying they had stripped down to cuddle as a way to express their love for each other. Police told them that pubic nudity in Thailand was a crime that carried a fine of up to 5,000 baht.

Drug tests on the couple were negative. The woman confessed and was fined 5,000 baht before being released. However, her partner grew agitated and was sent for a psychiatric examination at Koh Phangan Hospital. Police also asked immigration authorities to revoke their visas.

Surat Thani's deputy governor said nude sunbathing on the beaches of Koh Phangan was a regular occurrence, and that local officials arrested and fined violators.