Bangkok - Thailand's military has agreed to investigate reports that its navy pushed hundreds of Rohingya boat people back out to sea last month, leaving as estimated 500 missing and feared drowned, the army commander-in-chief confirmed Tuesday.

Prime Minister Abhisit Vejjajiva requested the investigation after meeting with human rights groups at a meeting Monday at which the Rohingya refugee situation was raised.

Thai Army Commander-in-Chief General Anupong Paochinda, while confirming Tuesday that the military will conduct the investigation, at the same time said he was confident no abuses had been committed against the Rohingyas, a Muslim minority group from Myanmar's Arakan State who have been denied citizenship by the ruling junta.

The Arakan Project, a non-governmental organization that monitors treatment of the Rohingyas, has claimed that Thai authorities on at least two occasions last month forced almost 1,000 Rohingyas back to sea in boats without engines and with scant supplies of food and water.

The Arakan Project has provided evidence based on the testimony of survivors that the Thai Navy between December 18 and 30 pushed some 992 Rohingyas in engineless boats back onto the high seas from southern Thailand.

Chris Lewa, coordinator of the Arakan Project, said there may have been more push-backs that she was unaware of.

"If some of the people hadn't survived we would never have known about these cases," said Lewa.

News that the Thai military was pushing Rohingya refugees out to sea came to light last month when the Indian Navy on December 18 rescued 107 people from a boat who claimed that they had been put to sea in the engineless craft by the Thai Navy and set adrift.

According to the survivors, about 300 of the 412 refugees had drowned when they jumped overboard to try to swim to shore.

Another group of 580 Rohingyas was allegedly shoved back to sea on December 30 in five boats after the engines were removed, said Lewa.

Of this group, some 193 onboard were rescued near Indonesia's Sabang Island in Aceh province on January 7 and an another boat with 150 onboard was rescued off Tillanchang Island, India, on January 10.

On January 6, another 81 Rohingyas were rescued by Thai fishermen, and have since been put under Thai military custody again, said Lewa.

The Arkan Project was still checking whether this group was part of the 580 pushed back on December 30.

There are still between 400 to 500 of the refugees unaccounted for, she said.

The Thai miliary has denied the accusations, although officials acknowledge that they see the Myanmar-Muslims as a security threat, suspecting them of coming to Thailand to join Thai-Muslim insurgents in southern Thailand's Pattani area.

"Definitely the reason for this is national security," said Lewa, speculating on the Thai military's drastic measures.

Lewa, who has worked with the Rohingya for years, said she was convinced the majority had landed in Thailand en route to Malaysia, where they can look for employment, paying brokers about 1,000 dollars for the passage.

The Rohingyas, numbering about 750,000 in Arakan, are stateless people, having been denied citizenship in Myanmar and Bangladesh.

Lewa called for Thailand to find a regional solution to the new wave of boat people.

"It's a regional issue," said Lewa. "Thailand cannot solve it alone, but should collaborate with the counties concerned and international agencies to find a solution to this problem."

Thai Foreign Minister Kasit Piromya has said he planned to meet with the ambassadors of Bangladesh, India, Indonesia, Malaysia and Myanmar to discuss the issue, should the allegations against the Thai navy prove true. (dpa)