A government-appointed commission began public hearings Wednesday into Sri Lanka's 26-year civil war despite criticism it lacks credibility and a proper mandate.

President Mahinda Rajapaksa appointed the commission in May, a year after government forces finally crushed ethnic Tamil rebels who had been fighting for an independent state, effectively ending the war.

Sri Lanka's C.R. de Silva, centre top, head of the Commission on Lessons Learnt and Reconciliation, listens as V. Nallaiyanaygam, centre bottom, a Tamil expatriate professional, speaks during the commission's first session in Colombo on Wednesday. (Reuters)He tasked the commission with determining why a Norway-brokered ceasefire signed by the government and the Tamil Tigers in 2002 collapsed and who was responsible.

But human rights groups have said the commission is a deflection of calls for an international probe of alleged war crimes, including government shelling of civilians and other issues.

The United Nations has said at least 7,000 civilians were killed in the last five months before the war ended in May 2009.

In June, UN Secretary-General Ban Ki-moon appointed a three-member panel to advise him on ensuring accountability for the alleged abuses during the war.

Sri Lanka refuses international probe

Sri Lanka has refused to co-operate with the panel or issue visas for its members, saying an external panel is an infringement of the country's sovereignty.

Commission chairman C.R. de Silva said in his opening remarks Wednesday that the time had come to "consolidate the military victory by addressing the root causes of the conflict and establish national integrity and reconciliation."

The commission began its hearings with presentations by the former Sri Lankan ambassador to the U.S., Bernard Gunatillake, and a former government peace negotiator with the Tigers.

Gunatillake said that the Tigers — who had claimed marginalization of Sri Lanka's minority Tamil population by the ethnic Sinhalese-controlled government — were not sincere in peace talks that followed the 2002 ceasefire and were buying time for another war.

Gunatillake called for the immediate resettlement of tens of thousands of war-displaced civilians still living in camps and the return of private land and houses occupied by the army, which he said were important steps for long-term peace.

Hearings also will be conducted in ethnic Tamil areas to allow people there to air their grievances, de Silva said.

The hearings will be held in public except when witnesses ask for a closed session or when sensitive security details are discussed, he said.