18,000 Rohingya Muslims have fled the worst violence to grip the area in five years

Burma's Rohingya Muslim ethnic minority members wait to enter the Kutupalong makeshift refugee camp in Cox's Bazar, Bangladesh. Photo / AP

More than 18,000 Rohingya Muslims, many sick and some with bullet wounds, have fled the worst violence to grip northwest Burma in at least five years, while thousands more are stuck at the Bangladesh border or scrambling to reach it.

A series of coordinated attacks by Rohingya insurgents on security forces in the north of Burma's Rakhine state and ensuing clashes triggered the Rohingya exodus, while the Government evacuated thousands of Rakhine Buddhists.

Since the attacks late last week, about 18,445 Rohingya - mostly women and children - have registered in Bangladesh, the International Organisation for Migration (IOM) said today.

"They are in a very, very desperate condition," said Sanjukta Sahany, who runs the IOM office in the southern town of Cox's Bazar near the border.

"The biggest needs are food, health services and they need shelter. They need at least some cover, some roofs over their heads."

Sahany said many crossed "with bullet injuries and burn injuries," and that aid workers reported that some refugees "gave a blank look" when questioned.

"People are traumatised, which is quite visible."

The United Nations, while condemning the militant attacks, has pressured Burma to protect civilian lives without discrimination and appealed to Bangladesh to admit those fleeing the military counteroffensive.

At least 109 people have been killed in the clashes with insurgents, Burma says, most of them militants but also members of the security forces and civilians.

The United Nations Security Council was briefed behind closed doors on the escalating violence at the request of Britain.

"There's a lot of concern about the situation in the country. We all condemned the violence, we all called on all the parties to de-escalate," British UN Ambassador Matthew Rycroft told reporters after the briefing.

The treatment of about 1.1 million Muslim Rohingya in Burma is the biggest challenge facing national leader Aung San Suu Kyi, who has been accused by Western critics of not speaking out for a minority that has long complained of persecution.

Rycroft said the Security Council looks to Suu Kyi to "to set the right tone and to find the compromises and the de-escalation necessary in order to resolve the conflict."

The Rohingya are denied citizenship in Myanmar and regarded as illegal immigrants, despite claiming roots that date back centuries.

- Reuters, AAP