Singaporeans should play their part to conserve water even as the Government builds critical infrastructure such as the Marina Barrage, said Prime Minister Lee Hsien Loong on Saturday.

Mr Lee was speaking at the barrage as guest of honour of Singapore's World Water Day celebrations.

He said that "sometimes cute and different ways" could be used to encourage people to conserve the precious resource.

One example, he added, was the recent Let Aaron Shower project, where a 19-year-old Singaporean pledged not to shower until enough people supported the conservation message.

"Please help save some water and make (water conservation) our national project," urged Mr Lee.

According to a report by national water agency PUB, Newater - made up of reclaimed used water - will meet up to 55 per cent of water demand in 2060, up from the previous projection of 50 per cent.

Treated seawater or desalinated water is expected to meet 20 per cent of the country's water demand by 2030 and up to 25 per cent of demand by 2060, up from 10 per cent now.

The new report also sets out PUB's plans for the next 50 years, which includes Singapore's move to have the means to produce at least 80 per cent of its own water by 2060, a year before the agreement to import water from Malaysia expires in 2061.