The state government has begun “preliminary planning” to expand the Kurnell desalination plant as Sydney dam levels continue to drop at record pace.

The plant is producing 250 million litres of water a day at present, but was constructed in such a way that capacity can be scaled up to 500 million litres per day.

Minister for Water, Property and Housing Melinda Pavey said the state was experiencing the worst drought on record and the desalination plant wad playing a significant role in maintaining Sydney’s water supply.