Sri Lanka's foreign minister has revealed that he had stopped Canada from raising during the talks a UN-commissioned report which alleges that the military massacred civilians in 2009 in the final stages of the Tamil rebellion.
Put to him in a BBC interview from Perth that Canada might boycott the 2013 meeting, Cameron said: "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 refused to say whether Britain might boycott the meeting."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," Cameron said.
Sri Lanka has condemned the UN-commissioned report as "preposterous", saying it is biased and reliant on anonymous, subjective evidence.