Rights groups and aid agencies have raised concerns after dozens of stranded Rohingya refugees, who landed at Bangladesh’s southern coast at the weekend, were sent to an inhabitable island in the Bay of Bengal.

Authorities said the 29 Rohingya were relocated to the controversial Bhasan Char island late on Saturday to prevent a possible coronavirus outbreak in the refugee camps located in the Cox’s Bazar district of Bangladesh.

“Bangladesh faces the tremendous challenge of assisting Rohingya boat people while preventing the spread of COVID-19, but sending them to a dangerously flood-prone island without adequate health care is hardly the solution,” said Brad Adams, the executive director of the Asian division of Human Rights Watch (HRW), in a statement on Tuesday.

“Any quarantines need to ensure aid agency access and safety from storms, and a prompt return to their families on the mainland.”

Bangladesh last year constructed facilities for 100,000 people on Bhashan Char, a muddy silt islet in the cyclone-prone coastal belt, saying they needed to take pressure off crowded border camps that are home to almost one million Rohingya.

They are the first group of Rohingya to be sent to the island, local government administrator Tanmoy Das told AFP, adding they were being looked after by navy personnel who had built the facilities.

Officials said the group – including 15 women and five children – were detained after coming ashore on Saturday from one of two boats suck at sea while trying to reach Malaysia.

The two trawlers – carrying an estimated 500 Rohingya women, men and children – were stuck in the Bay of Bengal after being rejected by Malaysia, which has imposed restrictions on all boats in light of the coronavirus pandemic.

Bangladesh has refused to let the fishing boats land on its territory despite United Nations calls to allow them in as a powerful storm bears down on the region.

Late last month, Foreign Minister AK Abdul Momen told Al Jazeera that the Rohingya refugees were “not Bangladesh’s responsibility”.

“Why you are asking Bangladesh to take those Rohingyas? They are in the deep sea, not even in Bangladesh’s territorial water,” Momen said, adding that there are at least eight coastal countries surrounding the Bay of Bengal.

So far, no coronavirus cases have been confirmed in the sprawling camps in Cox’s Bazar that house Rohingya who fled a 2017 military crackdown in neighbouring Myanmar.

The plan to move the refugees to Bhashan Char has been staunchly opposed by the Rohingya community.

The UN refugee agency UNHCR said on Sunday comprehensive assessments were needed before anyone is moved to the island, spokeswoman Louise Donovan told AFP.

“UNHCR has all preparations in place to ensure the safe quarantine of any refugees arriving by boat to Cox’s Bazar, as a precautionary measure related to the COVID-19 pandemic,” she added.

In mid-April, 396 starving refugees were rescued from a trawler stranded in the Bay of Bengal for more than two months. At least 60 people died on the boat.

The survivors were moved to transit centres near the border camps where they were quarantined.

Thousands of Rohingya try every year to reach other countries, making the perilous journey on crowded, rickety boats.