The Sri Lankan government's inquiry into alleged war crimes committed during the country's civil war is "fundamentally flawed", an Amnesty International investigation finds.

Sri Lankan inquiry into alleged war crimes is 'fundamentally flawed' (Getty)

The Sri Lankan government has said for some time that there is no need for an international inquiry into what happened at the end of its civil war in 2009 - despite widespread allegations of war crimes on both sides - because its domestic investigation is sufficient.

However there have been concerns that the inquiry, the Lessons Learnt and Reconciliation Commission (LLRC), is not going far enough.

Now Amnesty International has gone through all of the LLRC's publicly available transcripts and uncovered serious flaws and omissions.

These include its failure to properly pursue allegations of war crimes and crimes against humanity - allegations levelled at both government forces and the Liberation Tigers of Tamil Eelam.

Sam Zarifi, Amnesty International's Asia Pacific Director, said: "The Sri Lankan government has, for almost two years, used the LLRC as its trump card in lobbying against an independent international investigation. Officials described it as a credible accountability mechanism, able to deliver justice and promote reconciliation.

"In reality it's flawed at every level: in mandate, composition and practice."

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The LLRC was established by Sri Lankan President Mahinda Rajapakse in May 2010, when he promised there would be an accountability process after the war, alongside UN Secretary General Ban Ki-moon.

Amnesty's report suggests that since it was established the LLRC has failed to investigate credible allegations of human rights violations, including illegal killings, enforced disappearances, widespread shelling of civilian targets such as hospitals, and the use of civilians as shields.

Earlier this year, a Channel 4 documentary titled Sri Lanka's Killing Fields included footage showing the apparent extra-judicial massacre of prisoners by government forces, the aftermath of targeted shelling of civilian hospitals, and the bodies of female Tamil fighters who appeared to have been sexually assaulted.

Also examined in the film are alleged atrocities carried out by the Tamil Tigers, including the use of human shields, and footage depicting the aftermath of a suicide bombing in a government centre for the displaced.

The LLRC presents its final report in November this year, but Amnesty International said it viewed its efforts as already "failed".

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Mr Zarifi said: "The LLRC is the latest in a long line of failed domestic inquiries. Impunity has been the rule rather than the exception, now exacerbated by a post-conflict triumphalism that rejects all responsibility for abuses carried out by government forces."

There is still hope of an international inquiry after a UN panel of experts in April found credible allegations of war crimes on both sides in Sri Lanka.

It recommended establishing an "independent international mechanism" to investigate allegations, a call which was reiterated and backed by Amnesty today in the face of the apparent failings of the domestic inquiry to get justice.

Mr Zarifi said: "The international community must not be deceived into viewing the LLRC as a credible replacement for an international inquiry – this would allow war crimes and crimes against humanity to go unchallenged.

"Only an international, independent investigation can deliver justice to the thousands of victims of Sri Lanka's brutal conflict. Only then will the voices of victims really be heard. And only then can the process of post-conflict reconciliation begin to move forward."