But both G8 member Russia and emerging power Brazil -- which like China and India is a member of the "G5" that joins the second day of the summit on Thursday -- echoed China's calls for the currency debate to be taken up by world leaders.

Top Kremlin economic aide Arkady Dvorkovich said China and Russia would "state their stance that the global currency system needs smooth evolutionary development.

Brazilian President Luiz Inacio "Lula" da Silva said he was keen to explore "the possibility of new trade relations not dependent on the dollar" and India has also said it is open to the debate.

Pope Benedict issued a document to coincide with the G8, urging leaders to impose tough rules on the financial system. In the encylical, he called for "a true world political authority ... to manage the global economy" and avoid more "abuse" of the free market.