A five-year-old girl is fighting for her life in an induced coma after an 18-year-old P-plater plowed a gold BMW through a crowd of jubilant Newcastle Knights fans gathered to send their team off to the NRL Grand Final.

Ten people were mowed down in the horror smash in Wallsend, Newcastle, on Saturday morning. A 67-year-old man was also critically injured. The teen driver was arrested at the scene.

The carnage unfolded at about 9.30am on Newcastle Link Road at the Transfield Drive roundabout, where hundreds of diehard supporters had converged to cheer on the Knights ahead of Sunday's decider against the Sydney Roosters.

Newcastle Knights fans gathered along a roadside
Hundreds of Knights supporters lined the streets of Wallsend to send their team off to the Grand Final, moments before the horror unfolded. Via AP

'Excited' teen behind the wheel

The driver of the gold BMW, an 18-year-old P-plater, had reportedly been "excited" about sending off the Knights ahead of the Grand Final. He was taken into custody as emergency crews swarmed the roundabout.

Witnesses described scenes of pandemonium as the sedan tore through the crowd, sending bodies flying. Paramedics worked frantically to stabilize the most critically injured, including the little girl, who was rushed to hospital and placed in an induced coma.

NSW Police confirmed the 67-year-old man was also in a critical condition. Eight others were treated for injuries ranging from minor to serious.

Reporter's front-row view of chaos

The Sydney Morning Herald's chief sports reporter, Tom Decent, was interviewing fans when the nightmare erupted. He said word began spreading through the crowd that multiple people had been struck by a car and were severely injured.

"It went from this incredible, euphoric atmosphere to just silence and panic," one fan told the crowd of reporters who descended on the scene.

You could hear the screaming. Then you could see people on the ground, not moving. It's something I'll never unsee.

Premier's heartbreak

NSW Premier Chris Minns said it was heartbreaking to see fans who were sending off their grand final team caught up in such a terrible incident.

"Our thoughts are with everyone affected, especially the young girl and her family," Minns said. "This should have been a day of celebration for Newcastle."

Police have established a crime scene and are appealing for anyone with dashcam footage of the incident to come forward. The 18-year-old driver remains in custody and is assisting investigators.

A city in shock

The Knights are set to face the Roosters in Sunday's Grand Final, the club's first decider in more than two decades. What was meant to be a week of celebration for the Hunter region has been overshadowed by tragedy.

Fans who had travelled from across the region to line the streets of Wallsend were left shaken, many in tears, as emergency vehicles replaced the red and blue banners that moments earlier had fluttered in the spring breeze.

The Newcastle Knights released a statement saying the club's thoughts were with the injured fans and their families, and that players had been briefed on the incident.

NSW Ambulance dispatched multiple crews, including critical care paramedics, to the scene. Two rescue helicopters were also called in to airlift the most seriously injured to John Hunter Hospital.

Rescue helicopter and ambulance at the scene
A Toll rescue helicopter and NSW Ambulance crews at the scene in Wallsend as the critically injured were airlifted to John Hunter Hospital. Via AP

What happens next

Police are expected to lay charges against the 18-year-old in the coming hours. Investigators are examining whether speed, inexperience or a moment of reckless showboating was to blame.

Meanwhile, a city that had been counting down the hours to kick-off now holds its breath for a very different reason, praying the five-year-old girl and the 67-year-old grandfather survive the darkest day in Newcastle's sporting history.