The rights group, Tamils Against Genocide (TAG) said witnesses would be "deeply disappointed" by the UN Human Rights Council's decision on Monday to delay the publishing of the findings of a UN inquiry into mass atrocities against Tamils in Sri Lanka.

"We are deeply disappointed on behalf of our witnesses, who came forward to submit their testimonies and evidence of war crimes to the UN inquiry at grave risk to themselves and families back home," Jan Jananayagam, the director of TAG, which has worked closely with Tamils who were witnesses and victims of mass atrocities during the end of the armed conflict told Tamil Guardian.

"Hearing that the inquiry's findings will not be released at the Council's coming session is going to be extremely difficult for them to accept. In the interests of transparency, we stress that the evidence of mass atrocities should be published as soon as possible, regardless of any political changes."

On Monday the Council decided to give the Sri Lankan government six months to cooperate with the UN inquiry. The UN High Commissioner for Human Rights, Zeid Ra’ad Al Hussein, stressed the extra time was given in the hope of finding new evidence and on the "clear understanding" that the deferral of the report would be "for one time only".

There is no reason to with-hold Interim findings from this phase of the investigation," Ms Jananayagam said, pointing to the OHCHR Investigation on Sri Lanka's previous statement that it would be able to conclude its work without access to Sri Lanka.

"If the government of Sri Lanka now promises access to in-country evidence there needs to be transparency on what is being promised. Will the OISL be able to interview senior army commanders and will it be able to examine mass graves?"