"Clearly, the government is making a lot of effort, but we have some strong concerns. The UN is concerned over the lack of free movement of IDPs, particularly the 'closed' nature of the camps."

Frustrations

"We picked up great frustrations. I was told by many that they just wanted to go home," Pascoe said.

"I urged the government to allow people who were screened, to be allowed to leave."

Mahinda Rajapaksa, Sri Lanka's president, promised in a meeting with Pascoe on Friday to send nearly 300,000 Tamil war refugees held in military-run camps back home in four months.

Focus: Sri Lanka
Q&A: Sri Lanka's civil war
The history of the Tamil Tigers
Timeline: Conflict in Sri Lanka
'High cost' of victory over Tigers
Caught in the middle
Rajapaksa said he expects that new demining equipment will allow all the ethnic Tamil civilians in the camps to be resettled by the end of January, a statement from the president's office said.

However, Rajapaksa, brushed aside Pascoe's demand to start an investigation and hold accountable those found guilty of human rights violations during the final phase of the war.

"Considering the understanding that existed between the UN and Sri Lanka, President Rajapaksa said he did not expect the UN to pacify any members, big or small, about the situation in Sri Lanka," the president's office said in a statement.

"With the new [mine-clearing] equipment in use, and hopefully more to come, we expected the entire resettlement to be completed by the end of next January."

Aid groups say the camps are overcrowded and prone to disease, and fear monsoon rains will create a public health crisis.

The LTTE was defeated in May after a 25-year civil war. The conflict left between 80,000 and 100,000 people dead.

The LTTE fought for four decades for an independent ethnic-minority homeland in the north of the island.