The International Federation of Red Cross and Red Crescent Societies says lack of water and sanitation kills as many people each month as the recent tsunami.
A report published today coincides with the launch of the federation's ten-year Global Water and Sanitation Initiative (GWSI).
The Geneva-based federation said that the Asian tsunami-which killed more than 200,000 people-had again highlighted the need for clean water in emergency situations. But it said it was also concerned about the chronic need for water among the world's poor.
It said that worldwide more than three million people die annually from disease spread through dirty water and poor sanitation facilities.
"The disease burden caused by contaminated water or unsafe waste disposal in many developing countries is unacceptably high," said Uli Jaspers, head of water and sanitation at the federation.
He said that water-related illnesses accounted for 35 per cent of common recurrent diseases around the world.
Added to this is lost working time due to sickness or people having to fetch water from far away.
The federation said it already helps more than two million people every year in post-disaster situations through existing water and sanitation projects and was increasingly involved in longer-term developmental aid.
The GWSI campaign aims to increase the number of people it reaches over the next ten years, as well as contribute to the United Nations Millennium Development Goals on reducing poverty, hunger and disease.
"This means not just scaling up the size of the projects … but also improving the quality of the projects … and ensuring that the projects can be sustained by communities themselves to give a truly long-term impact," said Jaspers.
The project will focus on the world's poorest countries, mainly in sub-Saharan Africa, Southeast Asia and parts of the Caribbean and Latin America.
One of the UN's millennium goals is to halve the number of people living without water and sanitation by 2015.