The UN's senior political official is to travel to Sri Lanka this week to encourage the government to allow displaced civilians living in camps since the defeat of rebel Tamils to go home.
Lynn Pascoe, the head of the UN's political affairs department, said on Monday that he would leave for the Indian Ocean island on Tuesday at the request of Ban Ki-moon, the UN secretary-general.
Pascoe said that the UN has concerns over the slow implementation of commitments that Colombo made to Ban when he visited in May, days after the Liberation Tigers of Tamil Eelam (LTTE) were defeated by the military, ending a 25-year civil war.
"We have been concerned about the pace of progress since the secretary-general was out there," Pascoe said.
"We're particularly concerned about the [refugees] in the camps, and getting them out, getting them home.
"The secretary-general said that he would like for me to go out fairly quickly to deal with follow-up issues and where they're going.
"President [Mahinda] Rajapaksa agreed and so I'll be on the plane tomorrow with a small team."
Pascoe is expected to visit camps in the north of the island and meet Rajapaksa and other dignitaries over several days.
Ban and Rajapaksa spoke by telephone on Monday, talking about human rights issues, political dialogue with the Tamils and alleged accountability for rights abuses committed by both sides during the war.
Pascoe said that "a whole range of human rights issues need to be discussed", but added that he thought rights violations were not the sole responsibility of the government.
Colombo promised to allow 80 per cent of the approximately 280,000 Tamils in state-run camps to return home by the end of 2009, and Western governments and the UN are becoming increasingly aware of the prolonged nature of the process.
Many rights groups have said that those in the camps are living in derisory conditions and for longer than necessary.
The government has said that it needs to separate possible Tamil Tiger fighters from the IDPs and clear land mines before resettlement takes place.
The fate of two UN employees in prison in Sri Lanka, accused by the government of collalorating with the LTTE, is also of concern to the organisation. They have been held since June, yet have so far not been charged.
Additionally, a Unicef (UN children's fund) spokesman was expelled from Sri Lanka recently, being accused by the government of bias towards the Tamils, which the agency denied.
Both cases were discussed by Ban and Rajapaksa on Monday, Pascoe said.
The LTTE fought for four decades for an independent ethnic-minority homeland in the north of the island. The conflict left between 80,000 and 100,000 people dead.