Mangled pram but no baby: Nixon amid chaos

A distraught mother couldn't find her baby in an overturned and mangled pram after a car ploughed into a crowded mall in Melbourne, killing four people and injuring 20 others.

Victoria's former police chief Christine Nixon, who narrowly missed being hit, searched for a baby after seeing the overturned stroller.

"I went to help the woman who owned the pram ... and she just kept asking me, 'Where's the baby' and I don't know," Ms Nixon told ABC radio.

Ms Nixon spotted the mangled pram after the chaos on the corner of William and Bourke streets.

She said the child's distraught mother couldn't see her baby anywhere.

Ms Nixon said she thought the mother and child had been hit further up William Street.

"I think what has happened is (the child) has then been thrown ... out of the pram and been dragged along with the car," she told the ABC.

"I thought when I turned the stroller over that the child might've been in it, but luckily it wasn't.

"There were goods strewn on the footpath"

Ms Nixon had been crossing the road when the maroon sedan came crashing through.

"The car came down the pedestrian path and I just managed to step out of its way," Ms Nixon told 3AW on Friday.

"There were people yelling as the car came down and I turned around and it was about a meter from me and I just stepped back.

"The police were about two seconds behind it and the next thing we heard were shots."

The Royal Melbourne Children's Hospital was treating four children after the incident.