Investments in water infrastructure must be sustained if Asia is to succeed in reducing poverty and maintaining strong economic growth, the region's top development banker said Tuesday.

Asian Development Bank (ADB) president Haruhiko Kuroda said the global economic slump should not be a reason to cut back on investment in projects aimed at increasing water supply and managing waste water.

Economic growth, population expansion and the influx of people into cities have sharply raised the region's water requirements while increasing pollution risks, he told an international water conference in Singapore.

"This is actually the time to be sustaining and increasing financing to fuel infrastructure investment to be the engine of growth again," Kuroda said, according to an ADB statement.

"Stagnant investments in this sector may compromise our energy and food security, as well our economies and environment, creating a significant new threat to both poverty reduction and economic growth."

He said the crisis could present investment opportunities and that the business sector can step in to make up investment shortages in cash-strapped countries.

The Asia Pacific region accounts for more than half of the world's population.

In 2004, 635 million people in the region did not have access to safe drinking water, while 1.86 billion people currently lack access to adequate sanitation, the Manila-based ADB said.

About 10,000 delegates, including policy-makers, water technology experts, scientists and engineers are attending the Singapore conference.

Organisers said the meeting is a platform to help find solutions to the world's water needs.

Later on Tuesday, Singapore Prime Minister Lee Hsien Loong was due to open a high-tech, 3.65 billion Singapore dollar (2.52 billion US) facility that will treat used water from homes and industries and ensure the city state's long-term water needs.

The Changi Water Reclamation Plant is capable of treating 800,000 cubic metres (176 million gallons) of used water -- enough to fill 320 Olympic size swimming pools -- daily.