In 2005, the Australian Federal Government changed the eligibility criteria for deferring fees through to the Australia Tax Office (ATO) as a HECS-HELP debt.
Under the Higher Education Support Act (2003), from 2005 onwards, only Australia Citizens or Humanitarian Visa holders are able to defer their unit fees through to the ATO. Permanent residents are still eligible for the subsidised (non-discounted) Commonwealth Supported rate of fees while they reside in Australia, but MUST pay the invoiced Student Contribution Amount and Student Services and Amenities Fee up-front on or before the relevant census date.
This is the case in all Australian universities.
If, however, a student becomes an Australian Citizen part-way through their degree (or in the first teaching period), they will become eligible to defer their course fees for either the current teaching period or the next teaching period, depending on when they became a citizen in relation to the relevant census dates.