BANGKOK (Reuters) - A Myanmar man has confessed to the murder of two British tourists in Thailand, police said on Thursday.

The bodies of Hannah Witheridge, 23, and David Miller, 24, were found on Sept 15 with severe head wounds near where they were staying on the southern island of Koh Tao, known for its coral reefs and diving.

The island has a large community of migrant workers from neighbouring Myanmar, also know as Burma.

"The investigation has advanced considerably," deputy national police chief Lieutenant General Jaktip Chaijinda said.

"Three Burmese workers were detained and we took their DNA for testing. During the investigation one of them admitted to killing the two foreigners," he said.

Thai authorities have warned that the killings would scare off tourists and government leaders have been urging police to solve the case quickly.

The tourist industry accounts for 10 per cent of Thailand's economy and it has yet to recover from a slump in visitors during months of sometimes bloody protests on the streets of Bangkok that preceded a military coup in May.

Jaktip said the man who had confessed was being detained but had not been arrested. "We still have to wait for DNA tests results which we expect to have in 14 hours from now in order to confirm this," he said.