"Ultimately, its up to different member states to determine whether there will be an international process. We have presented information to them and we've made clear what we believe is the need for accountability and we rely on the member states judgement to follow through," acting UN spokesman Farhan Haq told a press briefing.
The UN Human Rights Council is expected to move a third successive resolution in Geneva next month censuring Sri Lanka over its lack of progress on human rights accountability and reconciliation with the Tamil minority after a brutal three-decade civil war.
British Prime Minister David Cameron said last year that his government would back calls for an independent investigation if Sri Lanka failed to have its own probe mechanism which has heightened fears that this year's resolution would be tougher than previous years.
The previous two resolutions, both moved by the US and supported by India, committed Sri Lanka to speedier implementation of its own reconciliation body's recommendations.
President Mahinda Rajapaksa early this week slammed the resolution as a grave crime against his country.