Survival among the wreckage of Bourke Street rampage

The parents of a baby boy killed in the Bourke Street rampage have said it is a "miracle" their daughter somehow survived.

Nawwar and Matthew Bryant's three-month-old son Zachary was the youngest victim of the horror at Melbourne's busy shopping precinct.

He was one of six people killed when Dimitrious Gargasoulas allegedly rammed his car into pedestrians. Another 30 were seriously injured.

Zachary's two-year-old sister, Zara, was also among the victims but survived.

"His life was basically robbed of him for no reason," Mr Bryant told A Current Affair.

"He's so fragile and so innocent and yet he was killed in the most heinous of instances."

The siblings were with a part-time nanny and asleep in their pram when the carnage started.

A policeman drove Zachary to hospital, knowing that his injuries were too critical for him to wait for an ambulance.

"I think someone at the scene who had a medical background just said there's no way they could wait for an ambulance, was my understanding of it. So they put him in a police car and drove him straight to emergency," Mr Bryant said.

Sadly, doctors pronounced him dead at Melbourne's Royal Children's Hospital later that evening.

"It was hard," Mr Bryant said.

"When they all walked in and said he was braindead, it was just surreal. Literally that morning I was playing with him in the living room and the next minute, you've got a doctor telling you that he's clinically dead."

Zara managed to live through the brutal impact of the speeding car and her parents say she was hurled 150m along Bourke Street, three quarters of a city block.

"She is a total miracle," Mrs Bryant said.

"She had a couple of fractures - a fracture on her neck and the spine. And also facial abrasions as well, so burns on her face on either side."

"A little bit of bruising on the brain, I think," Mr Bryant added.

The photograph of their pram, overturned and empty, was one of the iconic photographs from the Bourke Street incident.

"(That photo) really breaks my heart," Mrs Bryant said.

"It reminds me of a life I once knew. A pram that carried both my children everywhere I went and it's sad. Of course it really strikes a chord when I see it."

The grief is still immense for the parents after losing their son.

"One morning you're having breakfast with your kids and the next minute, you can lose one of them and it can be out of no fault of your own really."

But they have found the messages of love and support from all walks of life to be "almost uplifting".

Unfortunately though, Zara is not yet out of the woods.

The couple still need to pay for mounting medical and rehabilitation costs.

You can make a tax-deductible donation to help Zara's recovery through the mycause website.