The family of a child who was filmed riding unrestrained through the streets of Perth on a car luggage rack say they have been left "shell-shocked" by the incident.

Key points: The child was spotted on the roof of the car by several motorists

The child was spotted on the roof of the car by several motorists The driver of the car has been charged by police with dangerous driving

The driver of the car has been charged by police with dangerous driving The family says a wave of online abuse has left them further traumatised

The boy was filmed by motorists and home CCTV cameras on Friday afternoon as the SUV drove through several suburbs on streets including Tonkin Highway, which has a speed limit of 100 kilometres per hour.

Several motorists tried to flag down the boy's mother — who only wished to be known as Erica — as she was driving the car and alert her to the danger.

Police said the driver then stopped and placed the child, who the family say climbed onto the roof by himself, back in the car before driving away.

Police were then called and pulled the car over at a petrol station on Nicholson Road in Harrisdale. There were three children in the car at the time — two secured in child restraint seats and a 4-year-old boy who police allege was unrestrained.

A 36-year-old woman has since been charged with dangerous driving and summonsed to appear in court at a later date.

The boy's mother, named Erica, has fronted the media but did not answer questions. ( ABC News: Courtney Bembridge )

But family spokesman Gerry Georgatos, from the National Indigenous Critical Response Service (NICRS), said he would like to see the charges dropped, because the woman was not aware her child was on top of the car.

"I'd like to see the charge removed, I don't see there is any reason for dangerous driving because there was no presumption of the mother dangerously driving," he said.

"The mother cognitively didn't know her child was on the roof. The mother had presumed that her children were still restrained as she had buckled them up."

'Freakish' incident hits family hard

The family fronted the media on Tuesday for the first time since the footage was broadcast and described the event as "freakish".

Motorists filmed the boy riding on the roof of the car through the streets of Perth. ( Supplied: Channel 7 )

"What could have happened has shell-shocked the family, upset them to no end, as it would any family, any household, anywhere in the world," Mr Georgatos said.

"This is an extraordinary event, it was a freakish event, it was something unforeseen."

Mr Georgatos said the family was incredibly thankful the boy was not injured during the incident.

"They are just thankful, they are just counting their blessings that a miracle actually occurred," he said.

"A miracle occurred that the child wasn't actually injured, didn't fall off the roof rack, and this is where their trauma and their grief is acute at this stage at what could have happened.

"It would have been a shock to him too when the car started moving.

"Now it's about supporting the young child, supporting the other siblings and supporting the mother and father."

Erica, the mother of the boy, sits next to Gerry Georgatos while speaking to the media about the incident. ( ABC News: Courtney Bembridge )

Mr Georgatos said it was the first time the boy, who has five siblings, had climbed onto the roof of the car, after he managed to free himself from his child restraint.

He said the first thing the child's parents did after getting home was remove the roof rack from the vehicle.

Online trolls add to family's pain

Mr Georgatos said the NICRS would be providing trauma recovery support to the family to help them get through the episode.

He said the family's grief was compounded by the strong public reaction to the airing of the footage, with a wave of online criticism directed towards them.

"I've read some of the comments and that public spectacle that trolls sometimes jump on, and they are disturbing," he said.

"They are disturbing and they are cruel, they are insensitive.

"That also compounds trauma to be exposed to such public brutality."