A speeding driver who crashed at a South Auckland intersection, injuring a pedestrian, was chased by members of the public after trying to flee, a witness says.
The crash seriously injured the driver's passenger and a pedestrian was sent flying onto the pavement.
The car had earlier driven over road spikes, while the police helicopter was following it from the sky above.
Alya Ikof was standing close to McDonald's Manurewa when the crash happened in front of her with a huge bang, not long after 1.30pm today.
She said the driver had sped into Great South and Alfriston Rds intersection where it slammed into a BMW.
"When the car came through it was a big boom, everything happened so fast," Ikof said.
The impact appeared to knock the BMW into a traffic light, while one of the cars bounced off and sent a pedestrian flying about 1m through the air, she said.
"It wasn't a full on impact on her because I think if it had been, it would have been absolutely a fatal hit," she said.
Ikof rushed to the woman's side.
"I had gone down to her, just trying to keep her calm, letting her know help is on its way," she said.
"She was still conscious she was moving, however, she was shivering that's how I knew she was in shock."
Ikof's husband and friend were in the McDonald's carpark.
They said the car's driver fled on foot, despite appearing injured.
He was trying to get into cars in the carpark but members of the public came running after him, Ikof said.
"There was about maybe six guys trying to chase him down because they had seen him run off and how bad the car crash was and that someone was injured," she said.
"They were just ready to grab him."
Ikof said she later saw about five police cars a few hundred metres up the road where she assumed the man had been arrested.
One of the men who had been chasing the driver was there, she said.
A police spokesman said officers earlier saw the car driving at a "dangerous speed on Great South Rd in Takanini" at 1.35pm.
Police monitored it from the Eagle helicopter, but did not chase it, the spokesman said.
The helicopter team saw two people being dropped off at a home on Mahia Rd.
The car continued on but soon drove over spikes that had been laid by police across Mahia Rd.
"It then continued to travel erratically and at high speed," the police spokesman said.
"The vehicle was observed crashing into another vehicle and a traffic light at the intersection of Great South Rd and Alfriston Rd."
The passenger was taken to hospital and although the driver left the car, was found with moderate injuries nearby and arrested, the spokesman said.
The two people who were dropped off on Mahia Road were also arrested.
Police have closed roads near the intersection of Great South Road and Alfriston Road/Weymouth Rd.
These are expected to remain for at least a couple of hours, with motorists being advised to avoid the area if possible.
The Serious Crash Unit has been notified.