The first fight of the new parliament could be over income tax cuts, with Labor not prepared to support the coalition's proposed cuts several years away.
The coalition plans income tax cuts for lower and middle-income earners immediately, but also wants to flatten the tax structure in 2022 and 2024.
Treasurer Josh Frydenberg wants the entire seven-year tax plan legislated together.
"It is important that this is dealt with as a package because we are talking about not just immediate tax relief but also long-term structural reform," Mr Frydenberg said.
But Labor's Anthony Albanese, currently the unopposed front-runner for the Labor leadership, says his party isn't ready to go that far.
"We are prepared to support the first tranche, which is about low and middle-income earners. So the government shouldn't play politics with this," he told reporters in Sydney.
But he said no one could predict what the global and domestic economy would look like in a few years time.
"The truth is that our international global economic circumstance is very vulnerable," he said.
Mr Albanese's resistance could mean the coalition has to consider splitting up its tax cuts if it can't get them through the Senate without Labor's support.
Australian Associated Press