Footage has emerged showing a car driving erratically through a roundabout just moments before it ploughed into a crowd of Knights supporters at Wallsend.
Ten people, including three children, were injured in the crash about 9.30am on Saturday on Newcastle Link Road at the Transfield Avenue roundabout, police said.
Two people have suffered critical injuries, and eight others are understood to be stable. All were in the care of doctors at John Hunter Hospital on Saturday afternoon.
Assistant police commissioner Dave Waddell said a P-plater driving erratically towards the roundabout had lost control of the car and crashed into the crowd of about 1000 people, who had gathered on the roadside to farewell the Newcastle Knights team bus as it was heading to Sydney and the NRL grand final.
He said the driver was known to police, but would not specify beyond that.
Police, and the state's police minister Yasmin Catley, have said the Knights' departure was subject to extensive planning, and that officers were "out in numbers" along the estimated 20-kilometre stretch from the city to the motorway which was lined with more than 10,000 of the club's faithful.
A five-year-old girl and a man, 67, remain in a critical condition following the crash.
Another five-year-old girl; a two-year-old girl; four other men aged 48, 24, 25 and 57; and two women aged 31 and 63, were taken to John Hunter Hospital for treatment.
Police said the P-plate driver of the vehicle, an 18-year-old man, was arrested at the scene, was taken to hospital for mandatory testing, and would likely be charged.
Footage has emerged of the BMW driving quickly into the roundabout and briefly crossing over the white lane line on Newcastle Link Road seconds before the crash.
Assistant commissioner Waddell said a highway patrol officer was stationed at the intersection at the time of the crash.
"Unfortunately, a young 18-year-old P-plate, the driver, has been driving erratically, has lost control of the vehicle and then gone into the crowd," he said.
NSW Ambulance acting associate director of clinical operations Tim Troon said bystanders provided a lot of support.
"It made our job, you know, carrying out emergency service a lot easier," he said.
"So we'd just like to thank the people involved. It ripples through the community, these sort of events, and there's lots of people now involved in this incident.
"I'd also like to just extend a thanks to the emergency services that were involved today, that again have made a big difference in this situation."
Assistant commissioner Waddell said there were two other people in the car, in addition to the driver.
He said there was anger in the crowd following the incident.
"We had to get the three of them out of there because the crowd could turn on them," he said.
"Certainly the crowd jumped, came forward, and I suppose that we will investigate that.
"So our crash investigation unit will investigate the accident, our detectives will ... we'll investigate any other offences that may have been committed, but certainly there was a fair bit of angst there from the crowd who also jumped in and provided first aid and even CPR to different people.
"So we've got to thank the crowd for what they did do, but certainly we'll investigate the whole circumstances of what occurred."
At a media conference on Saturday afternoon, Ms Catley said a split decision can change everything.
"And that is what has happened here," she said.
"So many people have been affected by one person's split decision."
When asked if there should have been more police presence considering the expected crowds, Ms Catley said the incident occurred some distance from the Knights' home ground.
"We're 20 kilometres away from the stadium," she said.
"I think that's important for people to note. Police have done a lot of work in preparation for this, in preparation for tomorrow, as they always do.
"There was a Traffic and Highway Patrol officer sitting right here ready to close this intersection.
"For the long weekend, we obviously have multiple police resources policing the grand final down in Sydney, policing the Koori Knockout up towards the Hunter, and events in Newcastle for the event both today and tomorrow.
"So we have plenty of police resources with specialist commands for particular traffic and violent crime."
Newcastle lord mayor Gavin Morris said the city was heartbroken.
"There's no doubt about it. This was going to be a big day. It started out so joyous. It's going to be a day of celebration, and in one moment, in one second, a bad decision has a ripple effect," he said.
"So it's tough to go from an extreme high to an extreme low for us, but as I said, I mean, this is what we do well here in Newcastle. You know, we look after each other and we're going to do that."
Minister for roads and Member for Maitland Jenny Aitchison said it had been a "horrific start to the long weekend".
"There's absolute concern and compassion for those victims of this crime, but we also need to make sure that we understand it could have been so much worse," she said.
"I want everybody to take from it the reminder that those decisions that you make behind the wheel have consequences and that we want to make sure everyone is safe this long weekend."
