Thailand has deported dozens of Rohingya boat people back to Myanmar, an official said Thursday, despite a UN appeal to accept members of the Muslim minority fleeing sectarian bloodshed.

The 73 Rohingya, including 15 women, were sent back across the border on Wednesday after landing on the southern island of Phuket, said Ditthaporn Sasasmit, a spokesman for the kingdom's Internal Security Operation Command.

"The waves were high and it might have been dangerous to go further, so Thailand allowed them to come into the country and detained them as illegal immigrants," he said.

"Phuket immigration police sent them back overland via Ranong, where there is a border checkpoint."

The UN refugee agency has called on Myanmar's neighbours to open their borders to people fleeing a wave of communal violence in the western Myanmar state of Rakhine.

Clashes between Buddhists and Muslims have left at least 180 people dead in Rakhine since June, and displaced more than 110,000 others, mostly Rohingya.

Myanmar views the roughly 800,000 Rohingya in Rakhine as illegal Bangladeshi immigrants and denies them citizenship.

Although the tensions have eased since a new outbreak of killings in October, concerns have grown about the fate of asylum-seekers setting sail in overcrowded boats.

In a statement, New York-based Human Rights Watch urged Thailand to "scrap its inhumane policy of summarily deporting Rohingya, who have been brutally persecuted in Burma (Myanmar), and honour their right to seek asylum".

The group said some deported Rohingya were falling into the hands of people smugglers waiting for them at the Thai-Myanmar border to demand large sums of money to transport them to Malaysia.

"Those unable to pay the smuggling fees are forced into labour to pay off the fees, condemning them to situations amounting to human trafficking," it said.

Rohingya have for years trickled abroad to neighbouring Bangladesh and, increasingly, to Muslim-majority Malaysia. They sometimes land in Thailand, which has been criticised in the past for pushing Rohingya back out to sea.

About 500 Myanmar boat people swam to shore in Malaysia at the weekend after a 15-day sea journey, according to police there. Another died after being hit by a boat propeller when he jumped into the sea.