Up until this month, that would have put her below the minimum income threshold to start paying back her "sizeable" student debt under the Higher Education Loan Program (HELP), formerly known as HECS. But from today that threshold will be slashed from about $52,000 to just $45,881, forcing 136,000 Australians, including Ms Boylen, to start repaying earlier.

Many economists have backed the federal government move as necessary to start clawing back outstanding student debts, which have soared from $18 billion in 2009 to almost $62 billion as of 2018.

But some experts warn the new threshold could push low income earners into poverty.

Under the changes, those in the lowest income bracket will start repaying one per cent of their salary each year - or at least $9 a week. Those on higher incomes will still pay more, with a wage above $134,573 contributing 10 per cent or at least $259 weekly.

Andrew Norton of the Grattan Institute supported bringing down the threshold, saying most people earning between $60,000 and $95,000 will actually be repaying less than they do now as payment amounts were stretched out.

But Tracey West at Griffith University said her own modelling, which is still to be published, showed that meant overall repayment would slow down, not speed up.

While the loans do not accrue interest, they are indexed to inflation and Dr West said disproportionately affect women, who tend to live on lower incomes, move in and out of the workforce more often and hold onto debt for longer.

At the University of Canberra, economist Phil Lewis said the new threshold was necessary, noting student numbers had exploded in the decade since the Gillard government lifted the cap on university places.

"It's become quite serious budget problem." Dr Lewis said. "The system is already quite generous compared to say the US. That being said, a single person renting on their own or with kids will find it tough."

Dr West said "credentials creep" meant more students were pursuing postgraduate study and racking up extra debt to compete in a highly educated workforce.

"We need more education for students around what these loans actually mean, and when they're locked in to pay for subjects [on census date]," she said.

Both ANU postgraduate students Ms Boylen and Zoë Tulip said they felt the debt was shifting beneath them all the time - with thresholds dramatically lower than when they signed up.

"The biggest thing now is the insecurity," Ms Tulip said. "I had a plan but now I'm thinking 'Am I going to get a job and survive with this debt?' And this extends even past us to middle income earners now, everyone is telling me they're worried."

Ms Boylen said her original plan to buy a house in the next decade now looked unlikely.

"I took on this debt because I thought it was going to get me a better job but now it better be a great job," she said. "There's less time to make myself secure."

The National Students Union have called for the threshold to be raised back to $55,874, stressing it was always intended students would not have to pay back their education until they had begun to reap its benefit in higher wages.

In Australia, the minimum wage is $37,398 but the average salary sits a bit above $60,000.

Those experiencing financial hardship can apply to defer their loan through the Australian Taxation Office.

A spokeswoman said the ATO had approved almost 5000 requests to defer loans in the past financial year.

"We approve significantly more applications for deferments than we disallow," she said.

Students heading overseas must still repay their debt as do those still studying but earning above the threshold, but the government has stopped short of implementing plans to take debt out of deceased estates.

Dr Lewis said it was reasonable to treat HECS debt like any other on death but Dr West warned that would just shift the hardship back onto families.

Canberra Times