US president Barack Obama said today the leaders of G20 must work together to generate economic growth because world economies are "inextricably linked".
And Mr Obama, travelling to Canada just hours after lawmakers agreed on a regulatory overhaul, prodded his G20 colleagues to make good on their own promises to clamp down on the risky behaviour by banks blamed for unleashing the worst financial crisis in 80 years.
The G8 and G20 groups of countries are meeting in Canada this weekend to discuss how to handle the recovery from the global economic crisis.
Mr Obama said the G20 made progress in its last two meetings with its response to the "the worst financial crisis of our time".
The G20 group of rich and emerging economies banded together at the height of the financial crisis and committed trillions of dollars to fight a deep recession.
"This weekend in Toronto I hope we can build on this progress by co-ordinating our efforts to promote economic growth, to pursue financial reform, and to strengthen the global economy," Mr Obama said.
"This weekend in Toronto I hope we can build on this progress by coordinating our efforts to promote economic growth, pursue financial reform, and to strengthen the global economy," he said.
"We need to act in concert for a simple reason: this crisis proved and events continue to affirm that our national economies are inextricably linked."
The G20 pledged last year to co-ordinate a string of reforms by the end of 2012 and Obama can boast he has met the bulk of those commitments with the United States a model to follow.
Europe has yet to come up with comprehensive rules.
"We are just not working in tandem and it's not good enough," said Peter Skinner, a British centre-left member of the European Parliament which approves EU financial reforms. "This may ruffle a few feathers at the G20 this weekend."
The G20, which includes the world's biggest economies and two-thirds of its population, meets in Toronto on tomorrow and Sunday.
The G8; Britain, Canada, France, Germany, Italy, Japan, Russia and the United States meets tonight and tomorrow.
Brazilian President Luiz Inacio Lula da Silva was a last-minute G20 cancellation as he opted to stay home to deal with the aftermath of deadly flooding.
The G8 agenda focuses largely on development and aid for poor countries, although the overarching economic issues cannot be ignored.
As G20 delegations arrived, thousands of protesters organized daily marches tied to themes such as women's reproductive rights and poverty reduction.
A Canadian judge handed protesters a small and probably temporary victory today, restricting the muse of a controversial sound cannon used for crowd control.
Since the last G20 meeting in Pittsburgh last September, the global economy has strengthened but Greece's debt troubles have put a spotlight on the poor state of government finances among rich countries.
Germany and Britain have pushed ahead with plans to curb government spending. They argue that with fiscal health comes confidence, and that breeds growth.
The US, whose own deficits have soared to the highest level since World War Two, has pushed for patience, warning that the recovery may not be robust enough to withstand a simultaneous drawdown in public support.
Recent economic data has cast doubt on the strength of the recovery. Figures released today showed US economic growth in the first three months of the year was more tepid than first thought.