Australia has not suffered a recession for over a quarter of a century, having avoided the 2008-2009 global recession under the previous Labor government.

Talk of a global downturn has resurfaced in recent months as world organisations like the International Monetary Fund continually downgrade the economic outlook.

"God forbid we would ever have another recession," Mr Morrison told a Liberal party rally in Brisbane on Sunday, the fourth day of the federal election campaign.

"I don't want my children to ever have to live through a recession but if you stick to the policies of the Liberal National Party, that is the best defence that you can ever think of for going against a recession."

But he warned Australia would be held back under Labor because it wants to put a $387 billion "tax bomb" on the economy, a figure Treasury has distanced itself from.

Last week in a letter to shadow treasurer Chris Bowen, Treasury secretary Phil Gaetjens said his department was not asked to to cost Labor's tax policies and did not provide the $387 billion total figure.

Instead, Treasury was asked to complete costings based on individual details and specifications provided by Treasurer Josh Frydenberg's office.

"We are quite able to add up the numbers for individual measures," Finance Minister Mathias Cormann told Sky News on Sunday, defending the use of the costings.

Labor disputes the $387 billion figure because it includes $230 billion in unlegislated personal tax cuts that are not due until 2022 and 2024, which it opposes.

The senator was repeatedly asked how much of the tax cuts would go to the highest income tax bracket, those earning more than $180,000 a year.

He refused to put a dollar figure on the amount and disputed modelling by left leaning lobby group, the Australian Institute that put it at $77 billion.

"The highest income earners will continue to pay to 60 per cent of all income tax revenue generated in Australia," he repeatedly answered.

Shadow finance minister and Labor campaign spokesman Jim Chalmers said the interview showed the minister was "all at sea" on tax policy.

"Mathias Cormann and the Liberal Party ... need to fess up that their tax plan is designed to take money out of hospitals and schools and TAFEs and to give it to the wealthiest Australians in this country," Dr Chalmers told reporters at a Labor rally in Sydney.

On Labor's policy to restrict negative gearing to only new properties, Senator Cormann said it would cost the economy $31 billion.

But he said he wasn't aware of any modelling by Treasury of the impact it would have on the housing market.

"There is consist analysis out there that Labor's housing tax ... will lead to the reduction in the value of people's homes, will drive up the cost of rents," he said.

He was reminded by Sky News host David Speers that Treasury had previously said it did not say that Labor's proposed policies "will" reduce house prices, but said it "could" put downward pressure on house prices in the short term but in the long term they were unlikely to have much impact.

"You are quoting very old and outdated advice," Senator Cormann replied.

Australian Associated Press