By Waliur Rahman
BBC News, Dhaka
The United Nations refugee agency has asked Bangladesh to move more than 6,000 Burmese nationals living on a tidal island to a safer place.
Most Rohingya refugees have returned to Burma
The appeal came after a mission of the UN High Commissioner for Refugees and European Commission found the Rohingya ethnic group in "squalid" conditions.
Dhaka says the Rohingya are illegal immigrants and should return to Burma.
Dhaka gave shelter to 250,000 Rohingya refugees fleeing the Burmese junta in the 1990s but most have now returned.
Bangladesh has two camps in its south-eastern Cox's Bazaar district for more than 20,000 registered Rohingya refugees from Burma (Myanmar).
But the UNHCR says more than 6,000 unregistered Burmese refugees are now living on the tidal flats of the Naaf river, that separates Bangladesh from Burma.
The UNHCR officials who visited the group to see their condition on Friday said many had arrived after the 1994 cut-off date for receiving refugee status in Bangladesh.
"The Rohingyas are living in extremely risky, deplorable and squalid conditions on the river flats. They are vulnerable to seasonal high tides and flooding during the current monsoon season," UNHCR spokeswoman, Jennifer Pagonis, told the BBC.
She said the international community had been asking Bangladesh since late last year to move the group to a safer place as a matter of urgency.
But she said the government had not yet responded to the appeal.
The minister for relief, Chowdhury Kamal Ibne Yusuf, said he had received no formal request from the UNHCR or any other international body.
He said he was aware that some "illegal immigrants" from Burma were living inside Bangladesh.
"We are not in a position to recognise the illegal immigrants. If the UNHCR wants us to improve their living condition, they can submit a proposal and we'll be ready to discuss it only on humanitarian grounds," he told the BBC.
The Rohingyas who remain in Bangladesh refuse to go back to Burma in fear of persecution.