The former UN spokesman in Sri Lanka Gordon Weiss tells Channel 4 News that a leaked UN report into "credible allegations" of war crimes represent Sri Lanka's "Srebrenica moment".

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A leaked United Nations report estimates that tens of thousands of civilians were killed during the fighting between Sri Lankan forces and the LTTE - known as the Tamil Tigers in 2009.

The document cites "credible allegations" that government forces deliberately shelled civilians and repeatedly targeted hospitals. If proven, the allegations amount to war crimes and crimes against humanity.

The Tamil Tigers are also heavily criticised by the three member panel, and stand accused of forcing civilians to remain in the conflict zone and using them as hostages and human shields.

Gordon Weiss, the UN spokesman in Sri Lanka during the government's offensive against the LTTE in 2009, compared the war crimes claims to the infamous massacre of 7,000 men during the Bosnian war in 1995.

He told Channel 4 News: "This is Sri Lanka's Srebrenica moment, in fact it's a Srebrenica moment for the rest of the world."

A young Tamil boy stands behind a barbed-wire fence in the Menikfam Vanni refugee camp located near the town of Chettekulam in northern Sri Lanka (Reuters)

The UN is also criticised in the reporting for failing "to take actions that might have protected civilians." The panel says casualty figures collected by the UN should have been made public at the time.

Releasing the figures "would have strengthened the call for the protection of civilians while those events ...were unfolding" the panel concludes.

But conditions for aid agencies and UN officials on the ground were difficult.

Weiss told Channel 4 News they were at the "hard edge of humanitarian work" and were prevented from reaching the area by the Sri Lankan government. There "no foreign observers there to observe what was happening", Weiss said.

Weiss, who left the UN to write a book on Sri Lanka's civil war said he was "part of that structure" and "I bare my portion of the responsibility and blame for that."

He said that culpability rested on a "a fairly narrow range of senior leaders in Sri Lanka".

Click on the image above to read more of Channel 4 News' coverage on the Sri Lanka war
Click on the image above to read more of Channel 4 News' coverage on the Sri Lanka war.

The Sri Lankan Government, who received a copy of the report, said they found the report "fundamentally flawed in many respects" and that it was based on biased material.

In a statement on their website the Sri Lankan government said that it will respond in due course.

Weiss said however that he thinks ultimately there will be a war crimes tribunal:

"I think it will be very difficult for any of the great powers to ignore now what went on in Sri Lanka.

"It may well have been swept under the carpet, but this panel report has reversed the tide and I think we will see action.

"I believe we will eventually see a war crime process."

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The civil war, which lasted 26 years, officially finished in the summer of 2009 when the government forces pushed the LTTE forces into northern Sri Lanka and defeated them within an area designated the "no-fire zone".

Hundreds of thousands of civilians were trapped in the fighting and it's estimated that between 20,000 to 40,000 were killed.

In August 2009 Channel 4 News received a video showing naked, bound men being executed with a shot to the back of the head by two men who appear to be Soldiers.

The Sri Lankan government said the video was a fake, but in January 2010, a UN investigation said the video "appeared authentic". Following pressure from human rights groups and western governments the UN setup a panel into the end of the war.

He said: "I believe any inquiry will be narrowing on the circle of people around the Rajapaska family in Sri Lanka, who were ultimately responsible for driving and steering the decisions over this offensive."

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