The Australian National University confirmed on Tuesday that the ACCC was formally investigating centres in Western Australia and South Australia, which favour institutions that teach in those states.

An independent expert on education markets, Swinburne University pro-vice-chancellor Duncan Bentley, said the stoush was a sign of the sector outgrowing its regulations, as institutions competed more aggressively for overseas, domestic and online students.

Professor Bentley said global businesses were entering the Australian market and last century's rules were no longer relevant.

"You have so much diversity in student entry modes, and where and how they want to study," he said.

"The old world just doesn't cater for that. It's a bit of a furphy that you can operate universities within state boundaries these days."

WA's Tertiary Institutions Service Centre only processes applications for universities that teach in that state, while SATAC limits its membership to universities that provide unique courses for South Australian students.

Students from either state can seek enrolment in an interstate university but they generally pay between $30 and $60 to apply.

More than half of the ANU's students are from interstate – a larger share than any other Australian institution – which was one of university's motivations in complaining about the admissions centres' practices.

However, ANU deputy vice-chancellor Marnie Hughes-Warrington said there was "a moral argument" behind her university's push for an investigation.

"Students in disadvantaged areas, with little money, are just as worthy of receiving information about the opportunities open to them as students from more well-off backgrounds," she said.

"At present, they have to pay every single time they lodge an application. We just think that's not right."

A spokesman for SATAC said the centre was not exclusive, saying several non-SA providers, including Tabor College, CQUniversity and Torrens University Australia, had joined or were about to become members.

"However, our institutions have put in place a fee-for-service model that protects applicants from needlessly and pointlessly making multiple applications and paying multiple fees through different tertiary admissions centres for the same course," the spokesman said.

The Australian Competition and Consumer Commission would not comment on its decision to investigate the centres, saying it never discussed its inquiries until they were completed.

Professor Bentley said the tertiary education market was opening up quickly and there would be "massive amount of disruption" in coming years.

"There will be innovation everywhere. This is a $1 billion industry at the moment, and everyone wants to have a piece of the action, right through Australia and internationally," he said.

"It's understandable that regulations and structures that were set up to be state-based can't actually meet the requirements of universities today, which operate in many states and even overseas."

The ANU said the ACCC's decision to investigate the alleged anti-competitive behaviour strengthened the case for a single, national university admissions centre to replace the five state-based organisations.

"A national applications system might lead to better efficiency, make it easier for students to apply for courses at any university in Australia, and lead to a more rounded suite of services to cover international student admissions and accommodation preferences," Professor Hughes-Warrington said.