Deputy Prime Minister Michael McCormack attacked Ms Neville for rejecting a plan by his Victorian Nationals colleagues to expand the alpine storage.

"If it increases the capacity of water storage, provides security for South Australia, for Victoria and indeed for southern Riverina then that's got to be seen as a good thing," Mr McCormack said.

"(I'm) disappointed that Lisa Neville has made the comments that she has about not wanting to build dams because of climate change, what a load of bunkum.

"I can't understand why Victoria wouldn't want to come on board.

"This notion that it's never going to rain again, that's fanciful, that is just pie-in-the-sky stuff, it's just crazy and why wouldn't the Victorian government want to be part of the action when there's a willing and able Commonwealth government there with a cheque book ready wanting, willing and able to invest in water storage infrastructure and they're going 'hoo-hoo climate change it's never going to rain again', ridiculous."

Ms Neville hit back at the Nationals' leader's comments.

"Michael McCormack may be hoping for more rain, but here in Victoria we listen to the science that says our weather is getting hotter and drier and will continue to do so," Ms Neville said.

"In northern Victoria all our water is fully allocated, so Mr McCormack should explain which irrigators he wants us to take water away from to divert into a dam expansion.

"He would also need to convince his National Party colleagues to change their own rules that prevent further water being diverted from the Murray Darling Basin."