Bourke Street 'horror': Melbourne in mourning amid fears death toll will rise after car drives through mall.

“Surgery is still occurring. We still haven’t been able to be in a position to interview and charge that offender [but] that’s still our intention,” Victoria Police Chief Commissioner Graham Ashton said.

“Through the course of the weekend we will be looking to try and get that opportunity to step in and interview and charge that offender.”

It is understood police unsuccessfully attempted to stop him multiple times during the rampage.

Chief Commissioner Ashton said the man was known to police and had a history of violence.

He said police charged him on January 14 and had opposed bail but it was granted. He was scheduled to reappear yesterday.

Police said a 10-year-old girl was among those who died on the scene, along with a 25-year-old man, a 32-year-old woman and a 33-year-old man who died in hospital yesterday.

The Victorian Coroner has now taken charge of the investigation into the deaths, and will investigate a number of issues, including the police handling of the incident.

Chief Commissioner Ashton said the death toll could rise.

"The hospitals are still working on those critically injured people, but we do have fears — grave fears — for the health of at least two or three of those that are in that critical condition," he said.

"It may be that the numbers of people killed may still increase beyond four."

The Royal Children's Hospital said a three-month-old had been operated on and is in a critical condition, a two-year-old is in intensive care in a serious condition.

St Vincent's hospital admitted six people with serious but non-life threatening injuries and two people also checked themselves in with anxiety-related issues, as many in the city struggle with what Cr Doyle described as an "absolute horror".

Deputy Chief Commissioner Crisp praised Melburnians for their action during yesterday's incident.

"I don't know really how to put it into words, what people must have been thinking and feeling as this vehicle was travelling at high speed along Bourke Street ... it's extremely traumatic," he said.

"At the same time, situations like this, we actually see the best in people — in terms of police, Ambulance Victoria, the Metropolitan Fire Brigade, off-duty nurses and paramedics who quickly turned out to the scene and provided incredible support."

"But also to the broader community. Many, many members of the public just jumped in and did what they could to help."

"So this is horrific and traumatic, but we saw some incredible acts of bravery and people being prepared to help their fellow Melburnians and Victorians."

Counsellor from the Trauma Centre of Australia Peter Horton said he had been contacted by businesses to provide counselling for shocked workers.

"Basically we've got to respond to people who have been affected by the incident," he said.

"So they've actually seen their employees affected by the trauma and they want us to help."

Victoria Police Commissioner Graham Ashton said at 1:45pm yesterday the vehicle entered the city driving erratically and did "burnouts" on the corner of Swanston and Flinders streets.

Witnesses said there was "no hesitation" as the car drove into pedestrians in Melbourne's CBD, sending "people flying like skittles" and running for their lives.

Police have called for anyone who took photos or shot video of the incident to upload it their site.

Photos of an upturned pram were widely shared on Friday afternoon and Mr Horton said it was normal for people across the city to have been affected by the shock of the incident.

"There are people on the ground viewing things, there are people in the buildings viewing things, in addition to that there are response services," he said.

"But more importantly what is very, very daunting, the actual response by the media and the immediacy of the media to report what is going on - that becomes very real to everyone else who is listening on the radio, television or any other media.

"So it's not talking about thousands, but tens of thousands because those people have to build a story and an understanding about their own safety of going to a mall in the future."

Mr Horton said he had received two calls from businesses in Melbourne's CBD seeking to support staff.