British Prime Minister David Cameron has spoken to Sri Lankan President Mahinda Rajapakse and warned him that he must show progress on human rights in order to have countries attending the 2013 CHOGM and once again called for an independent investigation into war crimes.

Speaking at the 2011 CHOGM in Perth, Cameron aligned himself with Canadian Prime Minister Stephen Harper who has threatened to boycott the next meeting in Perth, unless war human rights law violations were addressed.

Speaking to reporters, Cameron revealed that he had met with the Canadian delegation to discuss Sri Lanka.

"I've been discussing this with the Canadians and I think we all have a similar view, which is we want to see Sri Lanka do more in terms of human rights, we want them to do more in terms of reconciliation after the defeat of the Tamil Tigers.”

"I've had that conversation myself with President Rajapakse, who's here.”

"They should be aware of the fact that they're holding this Commonwealth summit in 2013 and it's up to them to show further progress so they can welcome the maximum number of countries when they do."

He went on to say that there must be

"a proper, independent exercise to look into the whole issue of what happened, and whether there were war crimes, and who is responsible".

The British Prime Minister did not comment on whether or not he would be attending the 2013 CHOGM, but said Sri Lanka had to prove itself on human rights.

"The message I've given is look, the Tamil Tigers have been defeated, you're in government, you have an opportunity now to show magnanimity and also to show a process of reconciliation and to demonstrate to the rest of the world that you don't have things to hide.

It is very important that pressure is applied.

"

The comments on Sri Lanka came as Cameron made a plea to the Commonwealth to do more on human rights and take up the recommendations made by the Eminent Persons Group report.

In a speech to the other delegates, Cameron said,

"The Commonwealth is a great organisation, a third of the world's population, 54 countries across six continents, a really great network, but it is a network that must have strong values.

"The Eminent Persons Group report will strengthen those values particularly by having a charter setting out the rights, the freedoms, the democracy that we all believe in, and I think that is important."