Opposition Leader Malcolm Turnbull has dumped a member of his shadow ministry for crossing the floor in the Senate to vote against up-front tax breaks for carbon sinks.
Senator Fiona Nash, the now former-shadow parliamentary secretary for water resources and conservation, joined three other National senators in crossing the floor to back a Greens disallowance motion on the tax breaks yesterday.
The move directly defied Mr Turnbull, who helped design the tax breaks as environment minister in the Howard government and spoke in support of the scheme at a joint party meeting last week.
It is understood Mr Turnbull called Senator Nash yesterday morning to ask for her resignation, which she wrote up on the spot.
Senator Nash last night said that, although the decision to cross the floor had come at a personal cost, she said voting for the bill supported her rural constituency and she believed the tax breaks would allow big business to easily take over good farming land.
Senator Nash's axing came despite Mr Turnbull on ABC radio yesterday backing the rights of the four National Party senators to vote for the disallowance bill.
"We’re not like the Labor Party. We are a broad church and people are entitled to take a particular position on a matter of conscience," he said.
The Age revealed on Wednesday that the four National senators, Senator Nash, Barnaby Joyce, John Williams and Ron Boswell, along with Liberal senator Bill Heffernan, had spoken openly against Mr Turnbull’s position in last week's joint party meeting.
Senator Heffernan last night spoke against the legislation but refused to cross the floor.
The fifth National senator, Nigel Scullion, abstained from the vote, essentially saving his Human Services portfolio and avoiding division with his party colleagues in the Senate.
A spokesman for Nationals leader Warren Truss last night played down the decision to drop Senator Nash and said a replacement for her portfolio was likely to be named today.
"Mr Truss respects Senator Nash's decision and those of the other senators but understands because of her stand there was a price to be paid in terms of her ministerial position," the spokesman said.
The Age also revealed on Wednesday that Senator Nash had been involved in negotiations for several weeks with Greens senator Christine Milne, who spearheaded the disallowance motion.
Senator Milne said yesterday the tax breaks for carbon sinks, which are generally large tree plantations, came with little environmental oversight and would become a "tax rort" for large businesses.
Senator Milne added that big business would use the plantations as a way of getting around reducing their carbon emissions when an emissions trading scheme was introduced in 2010.
"What we have here is the plantation industry wanting yet another major handout from the public purse, along with the coal and aviation sectors, looking for a cheap way to avoid reducing their greenhouse emissions at source," Senator Milne said.
The Greens yesterday also presented the advice of Melbourne tax lawyer Michael Bearman, who later said the tax breaks extended to the land purchased for a carbon sink, despite explanatory notes put out by the Treasury Department suggesting the opposite.
Environment Minister Peter Garrett told question time the split vote in the Coalition showed Mr Turnbull had been unable to unite his party on the climate change issue.