US Treasury Secretary Jacob Lew described taxation reform as among the G20's most crucial initiatives Friday as the world's major economies look to close loopholes used by huge multinational firms.
Australian Treasurer Joe Hockey said Wednesday it was "hugely important" that G20 leaders agree to faster global growth targets when they meet in Sydney this weekend.
Canada allowed America's National Security Agency to spy on G20 talks in Toronto in 2010 and at the G8 summit days earlier, according to documents cited by public broadcaster CBC.
The International Monetary Fund warned the Group of 20 Wednesday that emerging economies were slowing more than expected and under pressure from US plans to slow its stimulus.
World leaders meet Thursday at a G20 summit in Russia where US President Barack Obama will strive to bridge deep divisions over his push for military action against the Syrian regime's alleged use of chemical weapons.
China's President Xi Jinping headed to Central Asia on Tuesday ahead of a G20 summit, state-run media reported, in visits expected to see energy deals and talks on slowing growth.
September 12-13, Head of State is expected to attend the meeting of the Shanghai Cooperation Organisation (SCO) Council of Heads of State in Bishek, Kyrgyzstan.
The OECD has presented the G20 nations with a bold strategy to crack down on tax avoidance by corporate giants and the super rich, and so boost overstretched national budgets.
The Group of 20 economic powers pledged "ambitious" steps Friday to spur growth and job creation to get the crisis-scarred global economy back on track.