World leaders are being urged to take action at this month's Earth Summit in South Africa to help developing countries manage scarce water resources.

The head of the United Nations Environment Programme, Klaus Toepfer, said governments had to move from declarations about improving access to water and sanitation to action and implementation.

Without adequate clean water, there can be no escape from poverty

Klaus Toepfer

Addressing the start of the World Water Week symposium in the Swedish capital, Stockholm, Mr Toepfer said more than a billion people around the world still lacked access to safe drinking water.

"Without adequate clean water, there can be no escape from poverty," he said.

"It is totally accepted around the world that it is the bottleneck for development, without any doubt."

The five-day gathering of some 900 politicians, scientists and industry representatives from 100 countries is due to end a week before the massive Earth Summit on sustainable development starts in South Africa.

Sanitation targets

Water is one of the five key themes United Nations Secretary-General Kofi Annan has picked for Johannesburg.

Sanitisation is also expected to top the agenda.

Mr Toepfer said water pollution, poor sanitation and water shortages would kill millions of people this year and leave millions more "in bad health and trapped in poverty".

Poor sanitation and dirty water will kill millions this year

Activists like the South African water minister Ronnie Kasrils want the same precise targets for sanitation that already exist for the supply of clean water.

"We are going to, in Johannesburg, have an almighty struggle for timeframes and target for sanitation, and I believe we can win," he said.

Officials attending the Earth Summit will make declarations and commitments that Mr Toepfer hopes will lead to action.

Taking the lead

But Margaret Catley-Carlson, of the Global Water Partnership, added a word of warning about putting too much emphasis on what governments do.

She said only a handful of the 65,000 people attending the Johannesburg meeting would be government officials.

"Sometimes governments lead, and that's great, that's the way we would like it to be," she said.

"Sometimes governments follow, and their citizens and their stakeholders and those who are represented in Johannesburg will get good ideas and will go ahead with these whether or not the governments are actually at the stage of endorsing the particular initiative."