More than 200 boat people held in southern Thailand will be pushed back out to sea, police said yesterday, despite calls by rights group to stop a policy that puts would-be asylum seekers at risk.

Around 259 people were found at sea on Saturday and were arrested for illegal entry.

Their discovery around 3 km (1.86 miles) from the coast follows what one NGO said was a "major maritime exodus" from neighbouring Myanmar of Rohingya, a mostly stateless Muslim minority group from the country's west.

"On average around 900 people left by boat from the middle of last month. We saw a major maritime exodus of nearly 10,000 people,” said Chris Lewa of the Arakan Project, a Rohingya advocacy group, addingthat increasing desperation was one reason for the departures.

Authorities in Thailand's Kapoe district said it was unclear whether any of the group were Rohingya but interviews with some of the group showed they were heading for Malaysia to find work or, in the women's' cases, join their husbands.

The 259 will be put back on boats and sent back to Myanmar, said Police Colonel Sanya Prakobphol, head of Kapoe district police.

"They are Muslims from Myanmar ... They are illegal migrants," Sanya told Reuters by telephone.

"If they come in then we must push them back ... once they have crossed the sea border into Myanmar then that's considered pushing them back. What they do next is their problem. ”

Tens of thousands of Rohingya Muslims have fled Myanmar's Rakhine state since 2012, when violent clashes with ethnic Rakhine Buddhists killed hundreds and made about 140,000 homeless.