DHAKA (REUTERS) - More than 1,400 Rohingya Muslim refugees set sail for a remote island in the Bay of Bengal on Saturday (Jan 30), a Bangladesh navy official said, despite opposition from rights groups concerned about the site's vulnerability to storms and flooding.

They bring to at least 6,700 the number of Rohingya refugees from neighbouring Myanmar that Bangladesh has sent to the island of Bhasan Char since early December from border camps, where a million live in ramshackle huts.

"We are ready to receive the new arrivals," Commodore Abdullah Al Mamun Chowdhury, the officer in charge of the island, told Reuters by telephone.

Five ships left with the Rohingya and their belongings after they were transferred from the camps to the nearby port city of Chittagong, he said.

Bangladesh on Friday moved 1,776 Rohingya to the island, which emerged from the sea just two decades ago and is several hours' journey away from the southern port.

The Rohingya, a minority group who fled violence in Buddhist-majority Myanmar, are not allowed to move off the island without government permission.

Bangladesh says the relocation is voluntary, but some of the first group of refugees, moved in December, spoke of being coerced. The government also says overcrowding in camps in the Cox's Bazar district fuels crime.

It has dismissed flood concerns over the island, citing the building of a 12km stretch of embankment 2m high, in addition to housing for 100,000 people, hospitals and cyclone centres.

Bangladesh has drawn criticism for a reluctance to consult with the United Nations refugee agency and other aid bodies over the transfers.

The UN High Commissioner for Refugees says the agency has not been allowed to evaluate the safety and sustainability of life on the island.

"We look forward to continuing a constructive dialogue with the government regarding its Bhasan Char project, including the proposed UN technical and protection assessments," it said in an e-mail.