Two were taken to Auckland Hospital, one in a serious condition and one with minor injuries.
Police and other emergency services were at the scene and the highway was partly blocked.
News cameraman Geoff Mackley arrived at the scene within about two minutes of the crash.
"It was swarming with police and unmarked police cars, plainly evidence of a car chase,'' he said.
He spoke to about six residents who lived in the nearby area, all of whom said they heard a large number of sirens followed by a "huge bang''.
Injured people were being treated at the scene.
It appeared one car had "T-boned'' another, causing extensive damage.
"I'd be surprised if there wasn't [serious injuries] if you look at the damage to the one car in particular, which was very significant.''
The wreckage of the cars was smoking when he got there "but it was quite hard to see that because they'd taken out the streetlights''.
The area had been sealed off.
