The Nationals leader declared his party would oppose any move to buy back more water for the Murray-Darling Basin Plan and warned city-based Liberals the issue was a "red line in the sand" for the regional party.
Labor will soon put legislation to the floor of Parliament to extend the Murray-Darling Basin Plan timeline, provide state governments with more funding to complete water saving infrastructure projects and open up the plan to more water buybacks.
The proposal could divide the Coalition. Some South Australian and inner-city Liberals quietly support delivering the full Murray-Darling Basin Plan, as voters pressure the party to demonstrate its environmental credentials.
Nationals leader David Littleproud said there was "no circumstance" in which his party would support Labor's plan to sacrifice "the people of regional Australia to the political altar".
"This is all about political gain in South Australia, and particularly in Adelaide, rather than understanding that they are going to destroy regional communities up and down the basin," Mr Littleproud said.
"That's not political leadership. That's political bastardry."
Mr Littleproud said the Nationals' were "our own sovereign party" and Liberal leader Peter Dutton was well aware of the rural party's position.
"From the very first moment I became the Nationals' leader, I made it very clear that water was a key tenant of Nationals' policy ... we cannot go away from those principles, otherwise that's a red line in the sand for us," Mr Littleproud said.
Liberal leader Peter Dutton was contacted for the party's position, but did not respond to questions.
South Australian Liberal senator and Leader of the Opposition in the Senate, Simon Birmingham, was cautious when asked if he supported Labor's proposal to extend the plan's timeline and open it up to buybacks.
"I'll be looking carefully at any proposed legislative amendments to ensure they are in the best interests of the river and river communities," Senator Birmingham said.
"Labor must be extra careful not to risk the long-term future of the plan by pursuing divisive policies that risk cooperation from Victoria, NSW or farming communities. This is a fragile process and having states walk away from cooperation could see everyone lose."
Fellow South Australian Liberal senator Anna Ruston was far more firm, stating she did not support the reintroduction of buybacks "without proper consideration of the socio-economic impacts on river communities".
"Taking the amount of water that is needed via buybacks out of river communities would decimate river communities like my hometown in the Riverland," Senator Ruston said.
"As a former primary producer from Renmark, I understand firsthand how our river communities cannot afford mass buybacks. Equally, I understand that a healthy and sustainable river system is in everyone's best interests."
Labor promised the legislation would be introduced in September. Although the extra time and money is broadly supported, the proposal to remove the 1500GL cap has been fiercely opposed in the regions.
Currently under the cap, the federal government can only purchase a further 225GL.
The Albanese government has promised to deliver the full basin plan, including the additional 450GL of environmental water, and it's feared removing the cap indicates the government will use buybacks to recover the majority of the environmental water.
Labor revealed the basin plan legislation would be paired with reforms to the water market.
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