Bangladesh could start relocating Rohingya Muslim refugees to a flood-prone island off its coast in the middle of next year, a government official said yesterday, as it pushes ahead with the plan despite criticism from aid agencies and rights groups.

Densely populated Bangladesh has seen an influx of more than 620,000 Rohingya to its southern-most district of Cox's Bazar, fleeing violence in neighboring Myanmar, since August. This week, it approved a $280 million plan to develop the low-lying Bhashan Char island to temporarily house some of them until they can go home.

The Bay of Bengal island, also known as Thenger Char, only emerged from the silt off Bangladesh's delta coast about 11 years ago. Two hours by boat from the nearest settlement, the island has no roads or buildings and it regularly floods during the rough seas of the June-September rainy season. When the sea is calm, pirates roam the waters in the vicinity to kidnap fishermen for ransom.

"We can't keep such a large number of people in this small area of Cox's Bazar where their presence is having a devastating effect on the situation on the ground environmentally, population wise and economically," H.T. Imam, Prime Minister Sheikh Hasina's political adviser, told Reuters yesterday.

"So, as quickly as we can shift at least some of the burden over to Bhashan Char, that will minimize the problem."

Mainly Muslim Bangladesh has said it aims to move about 100,000 refugees to the island. Some aid officials speculate that by raising the island plan, Bangladesh could be trying to put pressure on the international community to find a better solution to the crisis. But Imam, who holds the rank of cabinet minister, has denied any such tactic. He said the navy had started work on developing the island, money for which will come from the government.

Humanitarian agencies, however, have criticized the plan since it was first floated in 2015. "Having opened its doors to more than 600,000 Rohingya over the past three months, the Bangladesh government now risks undermining the protection of the Rohingya and squandering the international goodwill it has earned," said Biraj Patnaik, Amnesty International's South Asia Director, referring to the plan to move people to the island.