RIVERINA MP Michael McCormack has threatened to "cross the floor" on the Murray-Darling Basin Plan after the government added extra water to its recovery total.
The local politician is one of only a handful of Nationals members who have made their opposition to the basin plan clear.
The Coalition as a whole has never declared its stance on the plan, aside from leader Tony Abbott's mantra of "we won't accept a bad plan".
Mr McCormack said the basin plan was a "bad plan" made even worse by last week's announcement that an extra 450 gigalitres would be recovered from the basin.
"A week ago the Coalition states possibly would have signed off on the basin plan and, as long as it promised water savings through infrastructure roll-outs and compensation for affected communities, the federal Coalition would have been willing to do the same," Mr McCormack said.
"But this extra 450 gigalitres is a game-changer.
"Labor is looking after its Labor state mates and, out of the blue, they've made this nonsense announcement that just makes the whole thing even more devastating for the Riverina."
The coalition is not expected to announce its position on the plan until the final document is tabled in parliament next month.
If the party decides to support the plan and Mr McCormack crosses the floor, he will be following in the footsteps of his predecessor, Kay Hull, who took a similar stance against the sale of Telstra in 2005.