Developing countries, its main constituency, face "especially serious consequences with the crisis driving more than 50 million people into extreme poverty, particularly women and children," the bank said Sunday.
Bank President Robert Zoellick said some of the poorest economies are being hit by "second and third waves of the crisis." He said no one knows how long it will last or when recovery will begin.
"There is a widespread recognition that the world faces an unprecedented economic crisis, poor people could suffer the most and that we must continue to act in real time to prevent a human catastrophe," Zoellick said.
The bank will respond by tapping its healthy balance sheet to increase lending up to $100 billion over three years and launch initiatives in social protection, public works and agriculture, he said.
Zoellick spoke at a news conference that wrapped up weekend meetings of the World Bank and its sister institution, the International Monetary Fund, aimed at determining what additional action is needed to counteract the worst financial crisis in decades. The weekend kicked off with a meeting of finance ministers of the Group of Seven major industrialized nations that expanded into a meeting of the Group of 20 nations, bringing in such rising economic powerhouses as Brazil, India and China.