NSW Police Commissioner Andrew Scipione said.the footage showed the driver, now identified as 61-year-old Peter Zhurawel, had "detonated and self-immolated inside the vehicle" on Thursday night, causing flames that Mr Scipione described as "quite devastating".

Just seconds after the bright flash erupted from the Hyundai Getz, officers are shown in the footage running out of the police station and towards the car as it rolled down the driveway in flames just after 7pm.

The vehicle crashed into a wall before hitting the door of the underground garage, Mr Scipione said. The officers extinguished the blaze and dragged Mr Zhurawel, who was believed to be unconscious, from the car. They also removed an open gas bottle and petrol from the vehicle.

"There were a number of highway patrol officers there that clearly, clearly are brave, brave men," Mr Scipione said after viewing the footage.

NSW Ambulance paramedics treated Mr Zhurawel for serious burns to the front of his body, before taking him to Royal North Shore Hospital. He remained in the hospital's burns unit in a stable condition on Friday morning, and was under police guard.

No one else was injured.

Mr Zhurawel had been due in Fairfield Local Court on Friday morning over an apprehended violence order between him and his older brother.

The brothers are understood to have been involved in a dispute over the care given to their 93-year-old mother, of whom Mr Zhurawel is the primary carer.

Police sources told Fairfax Media that Mr Zhurawel had a history of mental health issues.

Detectives searched Mr Zhurawel's red brick home in Greystanes on Friday morning, and removed a number of items, including a computer and two gas cylinders.

Mr Scipione said police initially feared the incident was a terrorist attack, but had since ruled terrorism out as a motive.

"We know on the back of what we've seen internationally that police are at significant risk," he said.

"The reality is, on this occasion, what I can say is that this event is not in any way linked to a terrorist attack based on the briefings that I've received this morning.

"This [the alleged attack] is not the sort of action that we would say is anything but criminal. To do that is a crime, and that's the way we will be dealing with it.

"There is so much that could have gone wrong, so many people could have been in serious health, including members of the community. There were civilians that were walking across this footpath in the footage that I've seen, not seconds before, let alone minutes before, this event."

One source said it was a "very deliberate attack on the station".

The attack comes after a history of threats against the station, including a planned shooting that was allegedly uncovered late last year.

In November, a student from Arthur Phillip High School in Parramatta was charged after allegedly posting on social media, "merryland [sic] police station is next hope they all burn in hell" and "them lil piggies get shot". Arthur Phillip High is the school attended by 15-year-old Farhad Jabar, who fatally shot police accountant Curtis Cheng last October.

Mr Scipione said police had spent more than $320,000 upgrading security at Merrylands police station recently. Those upgrades included installing gates and ballistic glass, strengthening walls and installing cages around key areas at the station.

He would not comment on the motives of the alleged attacker, but said he was known to police.

with Nick Ralston