"The government was ruthless," said the aid worker, who asked to be identified simply as Joe. Joe has worked in the government-run refugee camps, but said he would not be able to return to Sri Lanka if he is identified.

"The situation in the country is not so conducive to the revelation of my identity," said the Tamil Catholic. "I am not unnecessarily worried about my life, but it has to go for a worthy cause."

Journalists, doctors and aid workers have disappeared after publicly questioning government policy or casting doubts on the government's version of events in the war zone, Joe said.

The 25,000 to 35,000 Joe claims were killed or injured in the last days of the war are in addition to the 6,500 killed and 13,000 injured in the first three months of 2009, according to United Nations estimates.

"Those who were killed and wounded were definitely more than 40,000," he said.

Joe bases his casualty estimate on reports that there were 330,000 civilians in the district of Vanni in March. At the time Sri Lanka's military dismissed that number, saying there were no more than 70,000 civilians in Vanni.

"But now 290,000 people have just come out of Vanni, not the internment  camps. If you make a little bit of mathematics, you know at least 30-to-40,000 people are still there, unaccounted for," he said.

War crimes were committed on both sides of the conflict, Joe said. Families who resisted Tamil Tiger demands for able-bodied fighters faced dire consequences, said Joe.

"They have been beaten by the militants and at times killed," he said.

Tamil Tiger demands for ever greater sacrifices led to Tamil-on-Tamil conflicts as the Tigers made their last stand.

"There was a lot of opposition from the people and there were clashes between the people and the militants. And there were sometimes injuries, and deaths also — relatively few, but it happened."

Joe hopes the end of the war will mean a new political culture in both the Tamil and Sinhalese communities.

"If you introduce a new way of thinking, a new way of living, new way of discussing things there is a lot of hope, but it all depends on how much the present political regime will pave the way for such developments," he said.

He also believes the Catholic community could play a role in healing the divisions of the last 26 years.

"The Catholic Church and the Christian community are the only ones to embrace both the communities — the Tamil-speaking and the Sinhalese," said Joe. "We are in a privileged position to influence the culture, to be a counterculture to the prevailing culture in the country."

Christians make up about 20 per cent of Sri Lanka's Tamil-speaking majority and about five per cent of Sri Lanka's population as a whole.

The Catholic witness for peace will be compromised unless the church can overcome its own divisions, he said.

"The church itself is split along the lines of ethnicity. I don't think anyone can deny that."

Diaspora Tamils protesting on the streets of Toronto, London and other cities with large Tamil communities have a role to play in urging international powers to put pressure on the Sinhalese-dominated government in Colombo, he said.

"They have every right to demand justice from the international community and I think they should continue with that," said Joe.

The first sign of a new spirit from Sri Lanka's military and its government would be to speed up resettlement of nearly 300,000 people currently in refugee camps.

"Keeping them in detention centres is against international humanitarian laws," he said. "At least now they have to be treated with humanity and with love and compassion, and put them back on their feet."