The toddler was thrown 150 metres into the air, but survived.

Her parents, Matthew Bryant and Nawwar Hassan Bryant, have told Channel Nine's A Current Affair it was "a miracle" that the toddler had survived being hit by the car.

"[We] can't even describe how amazing it is to us," Mr Bryant said.

Mr and Ms Bryant have spoken out nine weeks after the January 20 attack when 26-year-old Dimitrious 'Jimmy' Gargasoulas allegedly drove his car into the busy CBD mall, killing six people, including three-month old Zachary.

Mr Gargasoulas has been charged with five counts of murder and is expected to be charged with a further count of murder.

But Zachary's parents say they are yet to forgive how their "absolutely perfect" son was taken from them.

"He was the absolute light of our life, he was absolutely perfect," Ms Bryant said.

"Our whole life is basically just robbed of him," Zachary's father, Mr Bryant said.

Ms Bryant had asked the couple's nanny to take the two children home while she ran a few errands.

Both were asleep in their prams. Five minutes later, everything had changed.

"I gave her a ring, I thought I would just check on them. When she picked up the phone, that's when my nightmare started," Ms Bryant said.

"She told me 'something bad had happened'."

Both parents rushed to the hospital.

"I ran like madmen down Spring Street ... took a cab to the [Royal] Children's Hospital," Mr Bryant said.

Zachary's two-year-old sister, Zara, had also sustained injuries in the incident,including fractures and bruising on the brain.

Zachary was so severely injured, paramedics handed him to police at the scene, saying there wasn't time to wait for another ambulance to arrive to take him to hospital. Police rushed the infant to hospital in a patrol car.

The baby was declared brain dead later that night.

"It was horrible," Mr Bryant said.

"Even when they all walked in and said he was brain dead, it was surreal to me. Literally, that morning I was playing with him in the living room and the next minute you have got a doctor telling you he is clinically dead."

"I was in complete disbelief," Ms Bryant said.

"That was really hard."

They were allowed time to say goodbye.

"We were able to hold him again properly ... and have him in our arms and hug him one last time," she said.

In her eulogy, Ms Hassan Bryant described her baby boy as "perfect".

"He was the true definition of that word in every way," she said.

"From the moment I found out I was pregnant with him right until the time I laid him down to rest, he was just perfect."

Life also changed forever for Mohan Kumar and his wife Nethra Krishnamurthy???, who was returning to the office after breastfeeding her eight-month-old baby boy in day care when she was run over in Bourke Street.

The couple, who worked in the same building, had just stepped out for a coffee when tragedy hit.

"I could see the car coming ... hitting people, running down people," Mr Kumar said.

"I could see my death getting closer and closer."

But it was his wife who had taken the brunt of the impact.

"She had her eyes open, not blinking, not moving," he said.

"I felt I lost everything in my life."

But despite being injured from "head to toe" the new mother survived.

She spent 60 days in hospital and only recently returned home. She is still undergoing rehabilitation.