COLOMBO - CIVILIANS pouring out of the war zone in Sri Lanka's north are in dire need of emergency surgical and psychological help, an international aid group said on Thursday.

Medecins Sans Frontiers (Doctors Without Borders, or MSF) also voiced 'extreme' concern for 150,000 Tamil civilians still trapped by fierce fighting between government forces and Tamil Tiger rebels.

The statement is the latest sign of the aid community's alarm over the situation in northern Sri Lanka, where most agencies are barred by the government from working.

'MSF remains extremely worried about the situation for approximately 150,000 civilians remaining in the Wanni,' MSF said of Sri Lanka's northern jungles.

Most of those managing to escape the fighting were injured or traumatised, it said.

'The majority of the surgical cases are violence-related. The wounds are predominantly caused by shrapnel and shooting,' MSF said, without accusing either side of responsibility for civilian casualties.

'Many have lost relatives or even entire families. They have no contact with the family or friends and often do not know whether those they left behind are still alive.' Sri Lanka's government says that nearly 40,000 people have fled the fighting while placing the number left behind at fewer than 70,000.

Those who reach government-held areas are housed in controversial 'transition shelters' guarded by armed troops. Critics have described them as concentration camps.

'There is literally nothing for them to do except wait. In the camps, they have no jobs or schools. They have lost all autonomy. Their lives are on hold with constant fear about the safety of their loved ones,' MSF said.

The Sri Lankan military accuses the Liberation Tigers of Tamil Eelam (LTTE) of using civilians as human shields, and that escaping Tamil civilians are being well-looked after. -- AFP