Stockholm, August 26. 2011 - Investing as little as 0.16% of the world's gross domestic product - or $198bn per year- could give half a billion people regular access to safe drinking water within four years, a UN official said on Friday.

That would halve the number of people who risk serious illness and death on a daily basis, the United Nations Environment Programme said.

The findings are presented in the UN's Green Economy report, which also warns that if the global community continues to ignore water services investments, demand for water, risks outstripping supply by 40% before 2030.

UNEP spokesperson Nick Nuttall said the world total of people without access to safe drinking water currently totals about one billion people.

According to the report, people living in countries such as Cambodia, Indonesia, the Philippines and Vietnam are particularly prone to catching waterborne diseases because of the poor water sanitation there.

"Accelerated investment in water-dependent ecosystems, water infrastructure and water management, coupled with effective policies, can boost water and food security, improve human health and promote economic growth," said UN under secretary general and Unep executive director Achim Steiner.

Professor Mike Young, lead author of the water chapter of the report, said that "without this investment and policy reform, water supply crises will become increasingly common".

Unep said that more water productivity, recycling, new dams and desalination plants could largely help avoid increased drinking water scarcity but that money also needs to be put toward infrastructure, water policy reforms and technologies.

The findings were presented during this week's World Water Week in Stockholm.

Its participants also signed a statement urging next year's Earth Summit in Rio de Janeiro to commit to achieving "universal provisioning of safe drinking water, adequate sanitation and modern energy services by the year 2030".

That would include making water safer and more available, reducing water pollution, increasing the quantity of recycled water, and using water more efficiently in energy production, agriculture and the food supply chain.

GLOBE 2012 taking place on March 14-16, 2012 will bring world experts together to discuss how improved technology, infrastructure investment, and information-based solutions are helping to ensure adequate supply of water - a critical natural resource.