The idea was floated by Liberal senator Andrew Bragg in a speech to the Financial Services Council on Tuesday as a way of letting Australians act as if they were drawing down their super to help purchase property, while not necessarily draining their retirement savings.
It had "qualified support" from former Reserve Bank economist Peter Tulip, who told AAP tapping into super could mean buyers make more prudent decisions.
"If you use super as collateral, then people are putting at risk their own retirement balances so you would expect them to behave," he said on Tuesday.
"They (the coalition) have got some scheme that encourages more prudent borrowing and more prudent bidding."
He called the idea a "clear improvement" on the government's five per cent deposit scheme, which he said encourages buyers to take risks.
"The big problem with the government (five per cent deposit) scheme is that it's going to change behaviour," Mr Tulip said.
"It provides buyers with a one-way bet: house prices go up, they make a fortune, house prices go down, the taxpayer pays."
The coalition has taken a policy of letting Australians siphon $50,000 to buy a home through two unsuccessful election campaigns, while One Nation said it would allow workers to reduce their retirement contributions by a quarter to effectively give themselves a pay rise.
Labor has slammed both policies as unacceptably damaging to superannuation.
"That would be devastating for people's retirement incomes, it would make people worse off, superannuation is for retirement," Treasurer Jim Chalmers told ABC Radio on Tuesday.
"The Liberals, the Nationals and One Nation all want to vandalise that."
The government is clinging to maturing super to take pressure off the age pension in the coming years, as outlined in Treasury's triennial intergenerational report released on Monday.
But Senator Bragg said diverting 12 per cent of one's income to retirement savings coupled with the impacts of demand-side housing policies meant budding property purchasers were being hamstrung in their quest for a home.
"If Australians can reorient some of their super savings early in life .. they can optimise their objectives," he said in his speech.
Senator Bragg has previously copped heat for going AWOL on housing policy, when he criticised compulsory contributions at a National Press Club address in August leading to a dressing down from Liberal leader Angus Taylor.
The opposition leader on Tuesday stressed the proposal to use super as collateral is not coalition policy.
"It's Australians' money, they should have choice in it," he told reporters in Sydney on Tuesday, adding the opposition strongly supported self-managed super funds.
Senator Bragg took care to note he was merely spitballing during his address.
"We are keeping an open mind, and they are options worthy of a debate," he said.
