The global recession is thought to have pushed many millions into poverty
Christian, Jewish and Muslim leaders have urged the G20 leaders to remember the world's poorest people.
They said to forget the needs of the poor would be to "compound regrettable past failures with needless future injustices".
The religious figures published their joint statement in advance of this Thursday's G20 meeting in London.
The 32 signatories include Archbishop of Canterbury, Dr Rowan Williams, and Muslim leader Dr Mohammed Abdul Bari.
While acknowledging the "sheer complexity" of the challenge facing politicians, the statement called on them to restore "that lost sense of balance between the requirements of market mechanisms that help deliver increased prosperity, and the moral requirement to safeguard human dignity, regardless of economic or social category".
Roman Catholic leader Cardinal Murphy-O'Connor said: "At a time of economic difficulty, it is important for all political leaders not to forget their promises to the world's poor.
G20 LONDON SUMMIT
World leaders will meet next week in London to discuss measures to tackle the downturn. See
our in-depth guide
to the G20 summit.
The G20 countries are Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, South Korea, Turkey, the United Kingdom, the US and the EU.
"We pray for the poor, vulnerable and marginalised and also for the political leaders in their deliberations this week as we seek to create a more just world."
Dr Williams said people had high expectations of the meeting.
He added: "As religious leaders, we shall be praying that these expectations will be met and that the gathered politicians will be inspired to share a word of hope with all of us."
The UK government, which is hosting the G20 meeting, wants world leaders to focus on "co-ordinated macro-economic actions to revive the global economy, stimulate growth and employment".
It also says the international community needs to act to "support vulnerable emerging and developing markets".
Other religious leaders who have signed the appeal include Chief Rabbi Sir Jonathan Sacks and the the chairman of the Christian-Muslim Forum, Dr Musharraf Hussain Azhari.
The General Secretary of the Hindu Council UK, Anil Bhanot, and the Primate of the Armenian Orthodox Church of Great Britain, Bishop Nathan Hovhannisian, are also signatories.