The Group of 20, which represents 85 percent of the global economy, meet in France this week and have pledged to come up with concrete steps to boost growth as the world economy skids.
The Commonwealth includes five G20 members -- Britain, Australia, Canada, India and South Africa -- and in a communique at the end of a three-day summit in
Perth the bloc committed to do all it could to support the recovery.
It urged the G20 to "take the necessary steps to address current economic instability and to take concrete steps to put open trade, jobs, social protection and economic development at the heart of the recovery".
"This will provide the necessary confidence to global markets and ensure a more stable global economic environment," they said.
The communique committed the Commonwealth to avoiding trade protectionism and advocated "the importance of an open, transparent and rules-based multilateral trading system as a driver of global growth".
British Prime Minister David Cameron on Saturday reminded G20 leaders they must do everything in their power to remove barriers to world growth and avoid slipping back into protectionism.
Cameron, in Perth for the Commonwealth summit, held talks with his Australian counterpart Julia Gillard and said both of them agreed on the urgency in tackling imbalances in the world economy.
"On the G20 agenda, we both agree we've got to remove the obstacles to world growth, whether that is a deal in the eurozone, whether it is making sure there is no slide back into protection, whether it's dealing with the imbalances," he told reporters.
International Monetary Fund chief Christine Lagarde warned this month the weakness of advanced economies was "beginning to hit emerging countries" that had supported the world economy during the previous economic crisis.