HECS is the amount people have contributed to study at university - and what they pay back later through the tax system when they're earning a certain amount of money.
The debts are indexed on June the first every year in line with the consumer price index, currently sitting at around 7 percent.
Grace Francco from the National Union of Students says that this indexation means some people are stuck in a revolving door, unable to reduce their balance.
"Average HECS debt will increase by about $1500 this year and next year. So anyone who is earning less than $62,000 - which is between the minimum and median wage - will see their debt increase... So the minimum repayments that they make won't actually decrease their HECS debt. It will be - not even to break even."
A study by the Futurity investment group has found the bulk of graduates are carrying debt into their 30s, while over half still have debt into their 40s.
Futurity's Kate Hill says the work women do contributes to their HECS balance.
"Think about some of the more typical areas of study for females that are shown through the report, such as nursing and teaching. We see that the outcomes from a financial point of view as they move through their career, the pay is lower than some of the more tradionally male dominated industries."
Associate Professor Ben Phillips from the Australian National University says HECS can form part of a wider tax burden for women, as well as men.
"You've got a number of factors that lead to high effective tax rates. You've got your personal income tax you pay. So once you start earning say above $20,000 a year you start paying income tax. Now on top of that you might be losing family tax benefits, you might be paying childcare fees, you might be losing Centrelink welfare payments, but then of course you've got HECS on top of that. So for some people - not necessarily a lot of people - it will mean that they have that additional burden of paying back HECS at the worst time of paying high effective tax rates."
The size of HECS debts and the time it's taking to pay them down seems to be shaping important life decisions.
