File photo
Police said they were alerted about 6.40am after a car went off the road on State Highway 7 north of Waikari.
At least four fire crews worked to help free people trapped in the car, a Fire and Emergency New Zealand spokesperson said.
One person is in a critical condition and three others in a serious condition.
St John said it was responding with three ambulances and a helicopter.
At 8am, police said all four people had been removed from the car.
The was blocked between McRaes and Mt Alexander Rds.
The Serious Crash Unit has been notified.
"Traffic management is in place and motorists should expect delays."
- RNZ/Allied Media
