Questions are being asked about how the Melbourne terrorist who killed a receptionist in an apartment block was granted parole.
The issue will be discussed when state and territory leaders meet with Prime Minister Malcolm Turnbull this Friday.
It comes as Victorian Premier Daniel Andrews faces opposition calls to resign over the saga.
Mr Turnbull on Tuesday repeatedly questioned how Yacqub Khayre, who had a checkered criminal history before the siege in Brighton, was granted parole in November 2016.
“This terrorist attack by a known criminal, a man who was only recently released on parole, is a shocking, cowardly crime,” he said.
“How was this man on parole?”
Mr Turnbull has asked that question of Mr Andrews, saying it must be addressed.
It will also be of high priority at Friday’s Council of Australian Governments meeting.
“There have been too many cases of people on parole committing violent offences of this kind,” the prime minister said.
“It is clear that this is a real issue where people with known records of violence and, including people with known terrorist connections or at least connections, with extremists, have been released on parole.”
Watch: Gunman should not have been on parole: PM
Mr Andrews defended Victoria’s parole system, saying it was one of the toughest in the country.
Khayre had been compliant under the terms of his parole, including undergoing drug tests, observing curfew and attending appointments – but he wasn’t on parole for terrorism offences, the premier said.
All such matters would be part of an investigation and changes would be made if required, he said.
"As with all these matters though, we'll look at each and every element of the act and if there are learnings and improvements that can be made, we stand ready to do that," Mr Andrews said.
Victorian Opposition Leader Matthew Guy said that wasn't good enough, calling for Mr Andrews to step down.
"If Daniel Andrews can't keep Victorians safe then he doesn't deserve to be premier," he told SBS World News in a statement.
