One of Malcolm Turnbull's signature economic reforms has been killed in the Senate as he fights for his political life.
The federal government's plan to cut the corporate tax rate from 30 to 25 per cent was shot down on Wednesday, heaping pressure on the coalition to dump the unpopular policy before the next election.
The Senate voted to sink the tax cuts shortly after Liberal leadership challenger Peter Dutton pledged to abandon the policy.
"I don't think it's possible for them to go through and in that case I would support that money being applied either to households or a tax cut to small and micro-businesses," Mr Dutton told 3AW.
Finance Minister Mathias Cormann made a failed last-ditch attempt to drum up key crossbench support by carving out Australia's big four banks.
But the move did not win their support, with One Nation, Centre Alliance and independent Tim Storer voting against the cuts.
Senator Cormann took aim at Labor for opposing an amendment to exclude the Commonwealth Bank, ANZ, NAB and Westpac.
"If Bill Shorten was elected prime minister on his anti-business, politics of envy, socialist high-taxing agenda it will hurt the economy," Senator Cormann told parliament.
"Having campaigned supposedly against tax cuts for the big banks every single Labor senator voted in favour of tax cuts for the big banks."
But Labor frontbencher Doug Cameron lambasted the government over the leadership crisis engulfing the Liberal Party.
File image of Minister for Finance Mathias Cormann. Source: AAP
"When is Senator Cormann going to join his great mate, Peter Dutton?" Senator Cameron said.
"When is he going to join him and when is the end of this government going to actually happen? I hear that it's today."
He said the government should be funding health and education instead of giving an $80 billion handout to big business.
