Mr Brumby has vowed to confront Canberra's push for greater access to Victoria's irrigation water.

With leaders gathering in Sydney for this morning's Council of Australian Governments meeting, Mr Brumby fired a shot across the bows of Federal Water Minister Penny Wong and South Australian Premier Mike Rann, who want to speed up the buyback of water from irrigators in the Murray-Darling Basin.

South Australia is leading a push to lift the 4pc cap on the amount of water that can be traded out of any region of the Basin, in an effort to improve flows in the parched lower reaches of the Murray-Darling.

Victorian irrigators believe they would have most to lose if the cap were removed and they would be the first targets of Canberra's plan to buy back more than $3 billion in water.

Mr Brumby pledged to stand up for Victorian farmers and resist pressure from other States to lift the cap.

"We won't be supporting any increase in that cap," he said.

"The fact is, there's just no water around — whether it's water for farmers or water for cities or water for irrigators or water for the environment, we're all short of water."

The comments were echoed by the Victorian Farmers' Federation and the State and Federal oppositions.

State Opposition country water spokesman, Peter Walsh, said cap concessions would "lead to the decimation of irrigation communities throughout northern Victoria".

"The Premier must keep his eyes on the goal of protecting our productive industries in the midst of all the horse trading that will likely go on at COAG," Mr Walsh said.

There were fears in Victoria last night that Canberra might use its previous commitment of up to $1 billion towards the second stage of the Foodbowl Modernisation Project as a way to force Victoria's hand today.

Ms Wong indicated she was keen to see the cap lifted but gave no timeline.

"We do need to make the water market work as efficiently as possible," she said.