Seven people, including teenagers, have been taken to hospital after their car crashed in the mid-Canterbury town of Rakaia.
They were being chased by police but police say the pursuit was called off 20 minutes before the collision, just before 5am.
The car hit a fence and rolled.
Of those injured, two are critical and were flown to hospital, four are serious and one is moderate.
Deputy Rakaia Fire Chief Fred Clarkson said it was one of the worst crashes in his 27 years as a firefighter and the young people were lucky to be alive.