Australia's higher education regulator has revealed UTAS is one of two universities it is investigating, and is demanding information from at least another four on their responses to allegations of sexual assault and harassment.

The Tertiary Education Quality and Standards Agency this week confirmed it had made inquiries of every university outlined in February media coverage of hazing rituals, while the two higher-level investigations were triggered by complaints.

The agency has the power to revoke a university's registration should it be found in breach of federal legislation, part of which relates to student safety and wellbeing.

UTAS came under investigation following a complaint from advocacy group End Rape on Campus about the enrolment of a convicted sex offender.

The University of Sydney, the University of Newcastle and the University of Adelaide are among those understood to be issued with a "please explain" following reportage of hazing rituals.

Nina Funnell, author of The Red Zone Report into hazing traditions at universities throughout Australia, said it was "no coincidence" those mentioned in her research were the subject of agency inquiries.

"It's encouraging to discover that the Red Zone Report is influencing a response at a federal level," Ms Funnell said.

“Students and survivors are increasingly finding other mechanisms to hold universities to account and will continue to do so,” Ms Funnell said.

Previously, TEQSA has confirmed institutions are required to report any sexual assault or "incident of that severity" that happens on campus. Individuals can also report to the agency if they're unsatisfied with their university's response to a complaint.

"If we receive a complaint about sexual assault on an Australian university campus or any higher education provider, we will immediately investigate that," chief commissioner Nick Saunders told Senate Estimates in February.

"We will investigate that by, with the complainant's permission, going back to the provider and working with the provider to try and gather the evidence so that we can form an independent judgement."

End Rape on Campus's complaint about UTAS was expected to be finalised in June, a TEQSA spokesman said.

The group's 17-page complaint, lodged on behalf of an anonymous complainant, alleged the university flouted its own misconduct rules by allowing a man convicted of child sex offences and placed on the sex offender register to continue studying at the institution. 

TEQSA's four-person investigations team is expected to increase to between seven and nine people in the next financial year after its bottom line was boosted in the most recent federal budget.

End Rape on Campus argued the university's inaction endangered its student population and led to the complainant being so traumatised they dropped out of their studies.

Separately, the university recently issued an online update on its application for a renewal of registration, which ends on October 31.

More than 200 documents proving its compliance with the Higher Education Standards Framework (Threshold Standards) were submitted on May 4 as part of standard registration requirements.