Vic desal plant continues to sit idle

Victoria's $6.1 billion desalination plant will remain idle for another financial year at a cost of $1.8 million a day to taxpayers.

State water reserves sit at 71.4 per cent capacity, meaning the plant has remained idle since it opened in 2012 and won't get a water order in 2015-16.

Victorians pay $1.8 million a day to the builders even if no water is ever ordered.

"Desalination is our insurance policy against drought and climate change and guarantees Melbourne's water supply in times of low rainfall and emergencies such as floods and fires," Water Minister Lisa Neville said on Wednesday.

Labor signed the contract for the Wonthaggi plant in 2009 and defended the need for the project even as costs blew out and the plant sat idle.

Ms Neville says a rainfall-independent, large-scale water supply of up to 150 GL a year is vital for Victoria's water security.

The previous coalition government repeatedly criticised Labor's decision to build the large desalination plant, and the contract that guaranteed the builders money even when no water was ordered.

The plant was also investigated during its construction phase over links to bikies, organised crime and drug distribution.