Mr Secord visited the Illawarra and, along with Illawarra MPs Paul Scully and Anna Watson, called on the state government to get moving on the proposed plant.

Water Minister Melinda Pavey has been in talks with Wollongong City Council about the possibility of building a plant in the Illawarra and Lord Mayor Gordon Bradbery has said work would start mid-year "if the present drought and rainfall conditions continue".

"The Illawarra needs its own desalination plant," Mr Secord said.

"I think it's time the Liberals step up and commit to a desalination plant in the Illawarra for the South Coast.

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"This is a worldwide trend. In Israel, it's common, in the United Arab Emirates it's common, and when you go to Singapore it's recycled and desalinated water."

He said the United Arab Emirates' city of Abu Dhabi had eight major plants, Israel six and Singapore three with another two on the drawing board.

"We are the driest inhabited continent in the world, we live on the coast and it makes sense," Mr Secord said.

The desalination plant at Kurnell creates about 15 per cent of Sydney's water supply by turning seawater into drinking water, and can produce up to 250 million litres a day.

Mr Secord, who was involved in the discussions to build the plant when Labor was in government, said the water that came from desalination was perfectly fine.

"I've been in tours of desalination plants, the water is so pure they actually have to add minerals and nutrients to it to bring it up to normal drinking water standards," he said.

While it is understood no firm location for an Illawarra plant has been chosen, Mr Secord said it would need to be close to the coast and take up a similar footprint to "a Bunnings outlet".

Wollongong MP Paul Scully said the Illawarra needed "certainty" about its water security.

"The best time to start planning for the next drought is during the current drought," Mr Scully said.

"What we're calling for today is for the government to get on with the site location and scoping study and make sure the Illawarra water supply is secure over the medium and long term."

Minister Pavey said a desalination plant was one of a range of options being considered "to improve water security for Greater Sydney, the Illawarra and Macarthur regions".

"We want to reassure the Illawarra they are an important part of our future plans to improve water security across the state, particularly as the severity of the drought increases," Ms Pavey said