Scott Morrison and Bill Shorten clashed over climate change and tax breaks in a final leaders' debate held just 10 days out from polling day.
Mr Morrison used the televised debate hosted at the National Press Club in Canberra on Wednesday evening to again take his opponent to task on the cost of Labor's policies, which Mr Shorten said would be announced on Friday.
The question of costings emerged in an exchange about how the leaders would tackle climate change.
Labor has an emissions reduction target of 45 per cent by 2030, with the Coalition arguing there needs to be a careful balance between the environment and cost to the economy.
Mr Morrison has asked Mr Shorten why he would not reveal the cost of Labor's target.
"It's been now well over three weeks during the course of this election campaign, it's about 10 days or so that everyone will go to the polls. And we still haven't heard what the cost to Australians is," he said.
"Bill Shorten said it was a dumb question the other day. I don't think it is. I think it's a fair question."
But Mr Shorten would not budge, and maintained the cost of climate change was about more than just money.
"There was a cost to stop using asbestos in buildings. But I tell you what the advantage was — it saved lives," he shot back.
"When we've looked at the debate, cost is a dishonest argument when you don't look at the net benefit."
Both leaders had a chance to ask each other two questions during the final debate. All four questions focused largely on Labor's election commitments.
Mr Shorten asked Mr Morrison whether the PM would honour Labor's child care and cancer funding commitments if he retains government.
Mr Morrison quizzed Mr Shorten about the impact Labor's tax and negative gearing changes would have on small businesses and families across the country.
The men locked horns over ministerial appointments after the election.
Mr Morrison wanted to know who would take on the Home Affairs portfolio if Labor wins.
Mr Shorten refused to answer and asked whether Environment Minister Melissa Price, who has largely been absent from the national campaign, would retain her job.
Ms Price has been repeatedly criticised in the lead-up to the federal election over decisions relating to the Adani coal mine, as well as a lack of comment on the UN's extinction warning and other environmental issues.
Mr Morrison said she would keep her portfolio under a Coalition Government.
Mr Morrison: "No need to get nasty."
Mr Shorten: "I'm sorry if you think, I'm sorry if you think …"
Mr Morrison: "Smile, it was a joke."
Mr Shorten: "I'm sorry if you think that so many of your people leaving is the source of great amusement. I think it's more a judgement on the Government."
The leaders came together for the final debate after an emotion-filled day.
Both have condemned The Daily Telegraph for an article that accused Mr Shorten of omitting parts of his mother's history as a lawyer.
As the debate ended, Mr Shorten appeared to thank Mr Morrison for the comments he'd made on the article.
"Thanks for your comments earlier," the Opposition Leader said to the Prime Minister as they shook hands.
Look back over the entire debate in our live blog.
