Mr Ban asked world leaders not to forget climate change
United Nations Secretary-General Ban Ki-moon has called for drastic measures to protect developing countries against the global financial crisis.
He said central banks and the IMF might have to set up major credit lines to help poorer nations meet emergencies.
Mr Ban said the crisis might otherwise be a blow that many of the world's poorest people could not survive.
Meanwhile Asian and EU leaders called for the IMF to play a leading role in stabilising the world financial system.
Meeting in Beijing for the second day of a summit of 43 nations from the two continents, the leaders said they were moving towards consensus ahead of next month's meeting of the 20 largest economies in Washington.
"Leaders agreed that the IMF should play a critical role in assisting countries seriously affected by the crisis, upon their request," a draft summit statement said.
It added that the leaders agreed to "undertake effective and comprehensive reform of the international monetary and financial systems".
On Friday markets fell back amid fears of a sustained global recession.
Wall Street tumbled sharply following similar falls across Europe and Asia, before clawing back some ground.
Investors have been dumping shares worldwide because of gloomy prospects for the global economy - and are looking at other forms of investment.
Global money markets have showed renewed signs of stress, despite the billions of dollars that central banks and governments have pumped into the markets in recent weeks.
Investors worldwide are worried about falling share prices and the possibility of companies defaulting on their debts.
However, there was one glimmer of hope and a sign that banks may be more willing to lend to each other. Three-month lending rates among banks in the US and Europe dipped slightly.
'Short on resources'
In a meeting with heads of UN agencies, the World Bank and the International Monetary Fund, Mr Ban said the financial crisis could be the last straw for many of the world's poorest people.
He said the countries where these people lived faced the same pressures as the United States and Europe, yet many lacked the resources to withstand runs on their banks.
"It threatens to undermine all our achievements and all our progress," he said.
"Our progress in eradicating poverty and disease. Our efforts to fight climate change and promote development. To ensure that people have enough to eat."
Mr Ban said he would put the case for the world's poor at the Washington summit.
He also called for continuing efforts to pursue the Millennium Development Goals to eradicate hunger, poverty and disease, and to combat climate change.