SYDNEY (AFP) - A former Australian prime minister is among 28 prominent people on a list of alleged paedophiles, a senator has claimed in urging a public inquiry into child abuse be expanded.

Veteran Liberal senator Bill Heffernan used parliamentary privilege during a Senate hearing to claim he was in possession of the "very disturbing" police document, which allegedly focuses on legal professionals.

"We have in Australia, sadly, a compromise at the highest of levels. There is a former prime minister on this list and it is a police document," he told senators late on Tuesday (Oct 20).

"It's not so much the secret that's the problem, it's when a group of people, such as the 28 people on this page, keep each other's secrets that the institution is compromised."

Mr Heffernan, who has previously used parliamentary privilege to falsely accuse a former judge of using government cars to procure young men for sex in 2002, did not name names.

He claimed the list was handed to him by a police agency some time ago "because no one seems to want to deal with them". It was reportedly first uncovered during an inquiry into the New South Wales police force in the 1990s.

Mr Heffernan called for the terms of an ongoing and wide-ranging Australian inquiry into the child sex abuse to be changed to include the "institution of the law".

"I think it is time - like our churches and our other institutions who are now facing up to the truth - I think it is time the institution of the law faced reality," said the senator, who has campaigned against child abuse for decades.

The government-backed Royal Commission into Institutional Responses to Child Sexual Abuse was called in 2014 after a decade of pressure to investigate numerous allegations of paedophilia in Australia.

It has so far heard harrowing claims of abuse involving places of worship, orphanages, community groups and schools.

Attorney-General George Brandis said he did not have a copy of Mr Heffernan's documents and said it was up to the royal commission to decide what it investigates.

"Just because someone's name appears on a list doesn't make them guilty, and if there are serious allegations... they should be put in the hands of the police," he said.

"Nobody is above the law. I don't comment on... general allegations, but no one is above the law."