With the death toll expected to rise, it is understood Premier Daniel Andrews has convened a special cabinet sub-committee meeting on Sunday to discuss the tragedy.

The meeting is expected to discuss why the driver was  freed on bail, against the wishes of police, the week before he embarked on his rampage.

"Victorians are angry today – and I'm angry too," said Mr Andrews. "We want answers, and all of us can be confident that our government will honour the memory of those who died here with whatever change, with whatever resources, with whatever reform is required."

The Premier's comments came as the Coroner launched a forensic investigation into the incident, and as more details emerged about the criminal history of the alleged killer, Dimitrious "Jimmy" Gargasoulas, 26.

Known to authorities, Mr Gargasoulas had been charged on January 14 and appeared before an after-hours bail justice, who allowed him to walk free – despite police opposing his release.

He was due to appear in court on Friday but instead absconded, and later used his Holden Commodore to charge through the city, eventually killing five people: a 10-year-old girl, a 25-year-old man and a 32-year-old woman, a 33-year-old man, and a 3-month-old baby boy, who died on Saturday evening. Another four people were in critical condition, but police admitted they held "grave fears" for at least half of them. A further 30 people were being treated for injuries.

Chief Commissioner Graham Ashton said police made several attempts to arrest Gargasoulas once he absconded – and "yes there were some decisions made yesterday about when to terminate pursuits, and when to commence pursuits".  But he said the public could be assured that all decisions made were in the interest of community safety.

"It will be natural that people will want to speculate and make calls," Commissioner Ashton said. "But my police were on the spot; my police were the ones that had to make the decisions – life and death decisions in moments and seconds. And every one of those decisions, from my perspective, was made to try to prevent the loss of human life."

The actions of police, the mental health and drug history of the offender and the role of the justice system will now form part of the Coroner's inquiry. However, Mr Andrews has also vowed to look at bail laws "beyond the inquiry if we need to" and to make any necessary changes.

Victorian bail laws have already been strengthened in recent months, reversing the presumption in favour of granting bail to people charged with certain serious crimes. Instead, an accused now has to "show cause" as to why they should be released.

However in the wake of the Bourke Street tragedy, it is understood the government will consider issues such as whether there needs to be greater oversight of bail justices (who are often volunteers working after hours) and whether granting bail should be much tougher for certain types of offending.

"Let's properly understand what's gone on here, and then let's make, if necessary, a change that is fundamental to honouring the legacy and memory of those who have died," Mr Andrews said.

The Premier, the Chief Commissioner and lord mayor Robert Doyle paid tribute to victims on Saturday morning by laying flowers at a memorial outside the GPO Building, on the corner of Bourke and Elizabeth streets. On Sunday, the government will announce a new fund for people who wish to donate to the families of those killed in the Bourke Street tragedy. The state will contribute $100,000.

Mr Doyle said a commemoration book would also be set up at Town Hall from Monday, for those who wish to pay tribute to the victims. "I feel so sad, I feel so angry, I feel so gutted," he  said. "But you know something? Our community will go on even though there are so many who have been touched by this tragedy." 

with Neelima Choahan