Two people have died and several people have been injured in a crash near Christchurch.

Emergency services responded to the multi-vehicle pile-up on Main North Rd / State Highway 1, Sefton.

The crash happened shortly after 10am, and Hato Hone St John has transported two patients in a critical condition to Christchurch Hospital by helicopter and three patients in a moderate condition by ambulance.

Emergency services at the scene of a serious multi-vehicle crash on State Highway 1 at Sefton near Christchurch. Photo / George Heard 

Senior Sergeant Stephen McDaniel confirmed the double-fatal collision was between two cars.

“It appears that one vehicle left the side of the road and collided with the other coming from the opposite direction.

“We do not know the cause, but we know that one vehicle has crossed the centre line, hitting the other.

“We are still ascertaining the cause of the collision, so we’re currently at the scene, trying to figure it all out,” McDaniel said.

He said, “Police don’t want this kind of thing to happen at any time of the year, especially this time of year.

“We’re reminding people to slow down and drive according to the road conditions; distraction is a significant factor in many collisions.

“If you’re tired, pull over, and take a break.”

Images from the scene show debris from a flipped silver Hilux ute strewn across the road and a host of emergency workers at the crash site. A silver Corolla is off the road, in bushes, and has been covered with a sheet.

At least two stretchers were set up in preparation for the injured to be flown to hospital.

A witness at the scene said: “There’s a ute that has rolled in the middle of the road, and another car off to the side of State Highway One that has crashed. There are numerous emergency services on-site, and traffic is heavily backed up.

”There are two fire trucks and multiple ambulances; it appears that all the patients have possibly been transported to the hospital.”

He said that a second emergency helicopter had just left the crash site.

Motorists are being asked to avoid the area. The road is closed between Wyllies Rd and Broad Rd. 

Diversions are in place at Wyllies Road and Amesbury Road. 

Emergency services at the scene of a serious multi-vehicle crash on State Highway 1 at Sefton near Christchurch. Photo / George Heard 

“A helicopter was dispatched, and the Serious Crash Unit has been advised,” police said.

A Hato Hone St John spokesperson told the Herald: “We are currently on scene at this incident with three ambulances, one rapid response unit, one manager and two helicopters.”