Sri Lanka's Prime Minister Ranil Wickremesinghe said his government was not averse to international participation in the country's touted accountability mechanism, however stressed that "final judgement will be made by the internal judicial system".

The prime minister, who was visiting a temple in Guruvayur, said officials from neighbouring countries such as India, Pakistan, Afghanistan and Bangladesh would be able to participate in discussions on war crimes, alongside representatives from the US and human rights organisations.

Mr Wickremesinghe said Sri Lanka wanted to ensure that those responsible for civilian deaths are held to account, whether they were from the military or the LTTE, adding that the UN said it was possible that up to 40,000 people were killed in the last phase of the war.

"It was not clear how many of them were killed by the (Lankan) army or whether the LTTE had moved the people to the war zones which led to the death of some of them. We may not have the full expertise to identify the exact factors that led to those casualties. So international participation is welcome for determining such causes," he said.

"But the right to make the final judgment that was responsible for the deaths and on the nature of punishment should rest with the judicial system of Sri Lanka. The judicial system in Sri Lanka was in shambles earlier, but now it is returning to normal. The sovereignty of each country must be respected in such issues," he added.