PIDIE, Indonesia: The United Nations refugee agency (UNHCR) urged countries on Tuesday to help Rohingya Muslims stranded at sea as at least 20 reportedly died and hundreds more landed in Indonesia after weeks adrift in the Indian Ocean.

Nearly 500 Rohingya have reached Indonesia in the past six weeks while "many others did not act despite numerous pleas and appeals for help", the UNHCR said in a statement.

It said on Monday said 2022 could be one of the deadliest years at sea in almost a decade for the Rohingya with a growing number of them fleeing desperate conditions in refugee camps in Bangladesh. One boat carrying 180 people is believed to have sunk in early December, with all on board presumed dead, according to rights groups.

The Rohingya have long been persecuted in Buddhist-majority Myanmar, which borders Bangladesh. For years many have fled to neighbouring states like Thailand and Bangladesh, and to Muslim-majority Malaysia and Indonesia between November and April when seas are calmer.

Nearly 1 million live in crowded conditions in Bangladesh, including many of the hundreds of thousands who fled a deadly crackdown in 2017 by Myanmar's military, which denies committing crimes against humanity.

Rights groups have recorded a significant increase in the number leaving the camps, from about 500 last year to an estimated 2,400 this year. It is not clear what is driving the larger exodus. Some activists believe the lifting of COVID restrictions around Southeast Asia, a favoured destination for the Rohingya, could be a factor.

'DANGEROUS VOYAGES'

A boat washed ashore in Aceh province on the Indonesian island of Sumatra on Monday carrying 174 Rohingya, most of them dehydrated, fatigued and in need of urgent medical care after weeks at sea, local disaster agency officials said.

Some survivors recounted stories of hunger and desperation, saying more than 20 of the passengers died on the way.

"We came here from the largest Bangladesh refugee camp with the hope that the Indonesian people would give us the opportunity of education," said Umar Farukh, who spoke in a shelter crowded with Rohingya men, women and children receiving care from Indonesian medics.

Thai authorities said after rescuing six people found clinging to a water tank floating in the Andaman Sea that the survivors reported their boat being denied access to Malaysia and turning back towards Bangladesh.

Malaysia's Maritime Enforcement Ministry did not respond to requests for comment.

Monday's landing in Indonesia was the latest in a series of Rohingya boat landings and rescues around the region in recent weeks, prompting Bangladesh authorities to try and stop people from risking their lives on boats to Southeast Asia.

"We're doing everything possible to stop them from taking the dangerous voyages," Bangladeshi Refugee Relief and Repatriation Commissioner Mohammad Mizanur Rahman told Reuters late on Monday.