A 13-year-old girl is fighting for her life after a horror crash in rural Canterbury in the early hours of this morning that injured seven people.

A "suspicious" car travelling through Rolleston just south of Christchurch brought the attention of police at 4.22am.

Officers tried to stop the vehicle but it took off, starting a pursuit that was abandoned soon after "due to the nature of driving".

About 17 minutes later, the car was found more than 30km away by police on Bridge St in Rakaia.

It appears the car had struck a fence and rolled.

Police have confirmed there were eight people in the car.

A spokeswoman for St John said they got the call at 4.39am from police.

Two Westpac rescue helicopters and at least three ambulances were sent to the scene.

She confirmed seven people were rushed to hospital, including two in a critical condition. Four others have serious injuries while another is in a moderate condition.

St John later said one of the injured included a 13-year-old girl in a critical condition. Other teenagers were also injured.

A spokesman for Canterbury District Health Board (CDHB) said one patient had already been discharged. One was in a stable condition. Four had requested privacy. The CDHB said it was unable to get the necessary consent or permission to provide an update for the two other patients at this stage.

A police spokesman said: "Inquiries are ongoing to determine the circumstances around the collision.

The police serious crash unit has completed its scene examination and NZTA said the road had reopened by late morning.