Britain will vote for an international, independent investigation into alleged war crimes in Sri Lanka, British Prime Minister David Cameron said.

Cameron said on Friday it will vote in favour of the resolution on Sri Lanka at the upcoming United Nations Human Rights Council that has been moved by the US. 

The Prime Minister said he wanted to see reconciliation in the country which "President Mahinda Rajapaksa has failed to do". 

Regarding an international probe into war crimes against Sri Lanka, Cameron said "The UN Human Rights commissioner has called for this and that is what a UK co-sponsored resolution at the UN Human Rights Council supports." 

Welcoming the progress made by Sri Lanka in areas like reintegration of child soldiers, demining and reconstruction of conflict affected areas, the UK said it strongly believes "that, without a credible investigation in to very serious allegations of the past, it will be very difficult for the Sri Lankan people to move forward in the true spirit of lasting peace, reconciliation and unity and for Sri Lanka to reach its true potential".