THE government needed to spend R570bn over the next 10 years on "the full water value chain", Water and Environmental Affairs Minister Edna Molewa said today.

Ms Molewa is to deliver her 2012 budget vote in Parliament on Thursday afternoon. Treasury has allocated the Department of Water Affairs R29,3bn over the years 2012-15.

"It really goes without saying that government won't be able to fully fund that without tapping into other resources. We need to work with the private sector," Ms Molewa said at a Cape Town media briefing ahead of her budget vote.

Department of Water Affairs spokesman Sputnik Ratau said "the full water value chain" was everything from infrastructure building through maintenance to operations.

This year the department would invest "heavily" in bulk water provision, especially in developing the Mokolo and Crocodile River West augmentation project that would secure water supply to the developing Waterberg coal fields, the minister said. Already R2,7bn had been ploughed into this, and the project was "on track".

Providing regional bulk water supply would play a "significant role" in the budget vote, Ms Molewa said. The department wanted water provision to benefit some 500000 people this year.

Ms Molewa said R700m had been allocated to this, with about half of that ringfenced for the refurbishment of existing infrastructure.

Experts have warned backlogs in the maintenance of municipal water and electricity infrastructure threaten SA's economy and social stability. The National Planning Commission warned last year SA had to pay urgent attention to the management of water resources or risk having its development slowed.

The second phase of the Lesotho Highlands Water Project was also "on track" Ms Molewa said.

The project is set to add an additional 151-million cubic metres a year to the project's existing yield of 2986-million cubic metres a year by 2020, providing water to the Gauteng region, Africa's economic hub.