A proposal to allow young people to access their superannuation savings to pay off their student loans has been dismissed by experts as short-term thinking that would leave them worse off.

The Liberal senator Chris Back called on the government to adopt the idea, saying it would help people with the strain of repaying Higher Education Loan Program (Help) debts early in their working lives.

They could be required to make catch-up payments to superannuation later in their careers when they no longer faced the combination of mortgage costs and raising children, the Western Australian senator said.

But the higher education program director at the Grattan Institute, Andrew Norton, said it was a “terrible long-term” option for graduates because Help debts were only indexed at the inflation rate whereas money invested in superannuation attracted higher returns.

“Probably short of borrowing from your parents, Help debts are the most favourable loan conditions you’re going to get so, so it’d be costly in the long term to forgo high investment earnings to repay a low-interest loan,” he said.

“You’ve got a short-term cash-flow problem and the idea that you trade in superannuation earning 5-10% a year to pay off a Help debt increasing at 2-3% a year – overall long-term that is not a favourable economic decision.”

He added: “If the government allowed this they’d be setting up a lot of other debates about alternative uses of superannuation savings.”

Susan Thorp, a professor at the University of Sydney business school said the standard financial advice was for people to endeavour to pay off debts quickly “because usually the interest you pay on a debt is much higher than the interest you earn on in a savings account”.

However, she said Help debts were different from home mortgages or credit card accounts because they did not incur interest in real terms, and people did not need to start repaying the loan until they were earning at least $54,000 a year.

“It’s quite costly to people to transfer out of super to pay off their Help debt from lots of perspectives,” Thorp said.

“If I put one dollar in my super account at age 22 and allow it to accumulate at 7% per annum, by age 60 that dollar has increased to a value of about $13 in today’s dollars.

“If I just delay that dollar payment into super until I’m 27, a five-year delay, the dollar is worth about 30% less by age 60.

“Because people are being asked to make these substitutions at really early in their working life the effects on superannuation are large because of the loss of the effects of compounding over time.”

Back has promoted the idea as a way to help young people with their cash flow and also improve the federal budget by reducing the “skyrocketing” pool of unpaid Help debt.

“At a time when they really do have, if you like, a high liability, perhaps a young family, a mortgage or whatever, they’ve got this Help debt sitting over them,” he told the ABC’s AM program.

“When they have got that burden of, be it mortgages, be it children’s education or whatever beyond them, they can then accelerate that repayment to make sure that come the time of retirement they actually have got at least at much if not more.”

Back said he was “very hopeful that it will find its way into this year’s budget” or “find its way into our policies going forward into the 2016 election”.

But that appears unlikely. The education minister, Simon Birmingham, said the government was “very cognisant” of the specific aim of the super system.

“We have to be mindful that the primary purpose of superannuation is to support people’s retirement income, to prepare people for retirement and to alleviate long-term burden on our pension system,” he said.

The Labor leader, Bill Shorten, said his party was unlikely to support attempts to “raid” people’s superannuation savings, which should be used for retirement and not other purposes.

Labor’s shadow assistant treasurer, Andrew Leigh, said the idea did not stack up:

Hoping @senatorback can explain the benefits of using tax-advantaged super, growing at 7%, to pay off HECS debts, growing at 2.5% #auspol — Andrew Leigh (@ALeighMP) January 20, 2016

In early 2015, the then treasurer, Joe Hockey, encouraged a debate about allowing people to tap into their super savings to buy their first homes. Malcolm Turnbull, then the communications minister, dismissed it as “a thoroughly bad idea” and “not what the superannuation system is designed to achieve”.