Rohingya Muslims who paid hundreds of dollars to flee squalid Myanmar camps by boat are destitute since they were stopped at sea and returned, the U.N. refugee agency told AFP on Friday.

Images of hungry and thirsty Rohingya huddled on boats have stirred memories of a 2015 crisis, when thousands of fleeing Rohingya were stuck at sea as a trafficking trail south collapsed.

Some 120,000 of the stateless Muslim minority have languished in camps in central Rakhine for six years since a bloody bout of intercommunal violence with ethnic Rakhine Buddhists.

The end of the monsoon brings more favorable, if still treacherous, sailing conditions for those desperate to escape the camps that are branded as "open-air prisons" by rights groups and where Rohingya have little access to work, education or healthcare.

One Rohingya boat this week made it to Aceh on the northern tip of the Indonesian island of Sumatra but several others have been picked up in Myanmar waters and those on board sent back to the camps.

Many of the Rohingya had sold or lost all their possessions, including their shelters, to pay the extortionate fees to traffickers, said U.N. refugee agency spokeswoman Aoife McDonnell. They are in "acute need of support" now they are back in the camps, she said.

Journalists are not allowed to enter the camps except on brief government-chaperoned tours, but Rohingya there told AFP by phone that many also sold their food ration documents. "They have nothing to eat," one Rohingya in Thetkal Pyin camp said, asking not to be named. "They can't get their money back from the traffickers."