Bangkok  - The United Nations on Thursday called on the Thai government for a "transparent" investigation into reports that the navy last month took an estimated
1,000 Rohingya refugees out to sea and set them adrift in boats without engines or supplies.

"We feel very strongly that this needs to be the subject of a transparent investigation," United Nations High Commissioner for Refugees (UNHCR) regional representative Raymond Hall said.

Hall expressed his concern over the ongoing investigation after meeting with Thai Foreign Minister Kasit Piromya Thursday morning.

"Thailand has a long history of cooperating with the UNHCR on the refugee issue, especially with boat people," said Kasit.

Thailand has promised to cooperate with the UNHCR in finding a long-term solution to the plight of the Rohingya, a minority Muslim group from the North Arakan State in Myanmar.

Myanmar's junta denied the Rohingya citizenship in 2006, and has been persecuting the Muslim community of Bangladeshi origin since the early 1990s. An estimated
250,000 Rohingyas live in refugees camps in Bangladesh.

Thousands risk their lives annually searching for work in neighbouring South-EAst Asian countries. According to Thai authorities already 20,000 illegal Rohingyas are living in the kingdom.

Thai Prime Mister Abhisit Vejjajiva has promised an investigation into the claims that the Thai navy used undue cruelty to pushing back the Rohingya last month.

The incident has proven a major embarrassment for his newly installed government which has made the upholding of human rights and rule of law a priority.

But Abhisit has reportedly assigned the Internal Security Command Operation (ISOC) to conduct the investigation.

As ISOC is deemed one of the chief proponents of the Thai military's policy of pushing Rohingya refugees back to sea, both out of concern about the rising number of the Myanmar Muslims in Thailand and fears that they may join the insurgency in the country's predominantly Muslim deep South, there are doubts that it will thoroughly investigate the culpability of the Thai navy in committed abuses against the Rohingyas.

"It needs to be thorough and its need to be fast because we need to get a set of results that satisfies a broad number of stakeholders," Hall said of the investigation.

Reports that the Thai navy had beaten and dragged out to the high sea at least six boat-loads of Rohnigyas in December, began to emerge earlier this month based on the testimony of survivors who were rescued by the Indian and Indonesian navies.

The refugees claimed that at least 500 of the boat people have gone missing and are feared drowned.

The UNHCR was denied access to 126 Rohingya boat people - 80 of whom were allegedly victims of the December push-back - who were still Thai custody last week.

But the Thai foreign ministry said the 126 were "escorted" out of Thailand before the UNHCR could interview them.

The UN agency is now seeking access to a fresh batch of 78 Rohingyas who were captured by the Thai navy on Tuesday and are currently in a prison in Ranong province, about 500 kilometres south of Bangkok.

"I'm still waiting for the reply but I believe it will be positive," said Hall, of the UNHCR's request to see the 78 Rohingyas now under detention.

Kasit said the National Security Council and ISOC officials will meet Thursday to decide on the access issue for the UNHCR. (dpa)