BANGKOK (AFP) - The naked bodies of two British tourists were found on a Thai beach on Monday, the police said, sparking a murder probe on the popular resort island of Koh Tao.

The unidentified man and woman, both aged 24, were found stripped, with several wounds to their bodies close to a beachside bungalow on the island, a diving hot spot near Koh Phangan in the Gulf of Thailand.

"They were murdered and found naked on the beach. Police were informed at 6.30am," local police official Jakkrapan Kaewkhao told AFP on telephone. "Their bodies were found 30m from (the) bungalow," he said, adding the pair had arrived in Thailand on Aug 25.

Police are searching for witnesses and are yet to identify a suspect or motive, he added. An employee at the budget seaside resort where they were staying told AFP the bodies were found behind a set of large rocks on the beach.

"It was the first time this has happened on the island, I have never seen anything like this," the member of staff added, requesting anonymity.

Koh Tao is popular with tourists but draws fewer travellers than the neighbouring Koh Phangnan, home to the hedonistic "full moon" party.

Thailand's lucrative tourism industry has been battered in recent months after a prolonged political crisis ended a coup which saw the army blanket the country with a curfew and strict martial law.

Although the curfew was swiftly lifted from key tourist hot spots, visitor numbers are yet to rebound.

Thailand's military leaders have vowed to clean up the kingdom's tourist resorts after complaints of scams, assaults and even police extortion.