Treasury boss Martin Parkinson has rejected criticism that Australia has too narrow a focus for its G20 agenda during its 2014 presidency.
He believes a disciplined approach will be most effective.
The Treasury secretary also insists the group remains relevant, particularly at a time when the need for greater international cooperation is at its greatest against a significantly changed global backdrop.
Dr Parkinson is in Washington with federal Treasurer Joe Hockey to chair a two-day meeting of finance ministers and central bankers from the world's 20 richest economies, starting on Thursday.
In a speech, he said the group represents around 85 per cent of the world economy, 75 per cent of global trade and two-thirds of direct foreign investment, so is "naturally well-placed" to be a key global economic policy-making body.
He told the Centre for Strategic and International Studies the global financial crisis would have been much worse without the leadership and actions of the G20.
But he acknowledges it has shortcomings and its agenda has become "broad and unwieldy".
"Australia is acutely aware of this," Dr Parkinson said.
That is why Australia is running a tight agenda focused on promoting private sector-led growth and building global resilience, and "areas where it can best make a difference".
Some members have complained that issues like climate change have been dropped from the agenda.
But Australia is standing firm.
"Efforts to bring other issues into the G20 will be strongly resisted," Dr Parkinson said.
At this meeting finance ministers will thrash out ways to back a commitment made at February's Sydney meeting to raise global growth by two per cent over current projections in the next five years.
Other key issues will be IMF reform and financial regulation, as well as international tax reform to counter profit shifting and tax evasion.
