COLOMBO (AFP) - A top Norwegian peace envoy said he is willing to testify to any international war crimes investigation over alleged rights abuses during Sri Lanka's separatist conflict, a report said on Sunday.

Norway's former international development minister Erik Solheim said he was prepared to give evidence on the final months of the war in Sri Lanka, where he had tried but failed to broker peace.

"The war was won at a tremendous cost and I will (act as a) witness before any recognised international tribunal investigating Sri Lanka," Solheim told the local Ceylon Today weekly.

Solheim's mission was formally aborted by Colombo in April 2009, a month before the end of the decades-long war between the military and Tamil Tiger rebels.

Sri Lanka's war ended after a bloody finale by the military against the rebels fighting for a separate homeland for the ethnic Tamil minority.

The UN Human Rights Council in March voted in favour of setting up an international probe to look into allegations that up to 40,000 Tamil civilians were killed in the final stages, a charge Colombo vehemently denies.

A team of investigators is expected to be named shortly, but Colombo opposes any foreign inquiry.

"The war could have been solved through peace talks without military action," Solheim told the newspaper.

Solheim did not give details of the evidence that he would provide to any investigation. But he said he was aware of a top Tiger leader who tried to surrender during the final stages of the war, but had been killed.

Norway was invited to broker peace in Sri Lanka in December 1999. Solheim raised hopes of a peace breakthrough when he announced on November 1, 2000 that the elusive Tiger supremo Velupillai Prabhakaran was serious about talks.

A ceasefire arranged by Norway was torn up after Tamil Tigers tried to assassinate then army chief Sarath Fonseka in April 2006, a move that drew strong retaliatory attacks from government forces.