Access to water is increasingly seen as a potential global flashpoint, Singapore's prime minister said Tuesday.

Prime Minister Lee Hsien Loong said the pace and scale of urbanisation has intensified the challenge of providing safe, reliable and affordable water.

"More and more cities and countries see access to water as a security concern and a potential trigger of conflict," Lee said in a speech opening a series of conferences focussed on sustainable development.

"Global warming can aggravate this by altering existing water distribution patterns, intensifying droughts and disrupting the lives of millions, as is happening in Darfur," he said, referring to the Sudanese region where conflict broke out five years ago.

"However, scarcity of water is rarely the sole problem. As a whole, the world is not short of water," Lee told the gathering of more than 5,000 people from around the world.

He said there is a shortage of clean, fresh water where people need it, and lack of sound water management is a large part of the problem.

"It is not enough to build the best water treatment plants and then neglect to protect the water catchments from squatters or pollution," said Lee, adding technology and research play vital roles in water management.

"There have been breakthroughs in water technologies, more so than in clean energy," Lee said, noting that desalination, water reuse and other water purification techniques have become significantly cheaper.

"More water is available, at the right price. With a workable funding model, it is possible to build and operate water factories on a sustainable basis.

Lee said water management is a critical element of sustainable living, alongside conservation of resources, good air quality and sound urban planning.

The world's top climate scientists predicted last year that billions of people would face water scarcity and hundreds of millions would likely go hungry as damage to Earth's weather systems from greenhouse gases changed rainfall patterns, punched up the power of storms and boosted the risk of drought, flooding and water stress.