Big business tax cuts have been ruled out "100 per cent" if the coalition wins the election, despite Scott Morrison spending years arguing for them when he was treasurer.
Former prime minister Malcolm Turnbull in August dumped the controversial plan to slash the corporate tax rate for large businesses from 30 to 25 per cent, after the Senate refused to pass it.
The coalition managed to pass tax cuts for businesses up to $50 million, but Labor linked the bigger business cuts to the unpopular big banks and the Senate backed the opposition.
Mr Morrison argued strongly for the corporate tax cuts when he was treasurer but on Thursday said they would not be passed if the coalition wins on May 18.
"I can absolutely rule that out. Absolutely 100 per cent," the prime minister told reporters in Port Macquarie on Thursday.
"We will not be increasing or reducing taxes for businesses of more than $50 million in the next term of parliament."
Mr Morrison also said he had not discussed the issue with potential crossbench senator Clive Palmer, who was in favour of the cut, or United Australia Party officials.
"Never had a discussion with the UAP about it. Weren't looking to have one. They didn't ask for one," he said.
"So that is an absolute thing I can categorically, completely rule out."
Labor is attacking Mr Morrison over the aborted policy in a new advertising campaign with clips from his time as treasurer.
"We are pursuing our enterprise tax plan, nothing's changed on that," he says in the old footage.
"We remain committed to this, see we don't flip and flop around these things."
Meanwhile, Mr Morrison and deputy Labor leader Tanya Plibersek disagreed on Thursday about whether the deal to send detained asylum-seekers to the United States could be expanded.
"We would continue to work with the United States in the hope that the United States would take the total number that they have offered and perhaps more," Ms Plibersek told ABC radio.
But the prime minister insists there is still plenty of room to move within the existing agreement to get people off Manus Island and Nauru.
"We've still got hundreds of positions that can be filled under that arrangement," he told reporters in Port Macquarie.
More than 500 people have been sent to the US under the resettlement deal, with 1250 places on offer. There are roughly 900 people left on Manus Island and Nauru.
Labor leader Bill Shorten repeated his commitment to look at a deal with New Zealand to take detained asylum-seekers, but Home Affairs Minister Peter Dutton said it wasn't in Australia's best interests.
Labor will release its policy costings on Friday, more than a week before election day and significantly earlier than previous oppositions.
