The acting principal of a Christchurch high school where two boys involved in a double-fatal crash were former and current students is calling the incident a "tragic situation".

Friends and family of the two 16-year-olds killed in the crash have spoken out about their grief on social media and named the deceased as Rose Brown and Dexter Barham.

Three other people were injured in the crash involving two cars north of Christchurch yesterday morning.

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It is believed the driver who caused the crash might have been driving illegally, on a learners licence without the supervision of a motorist holding a full licence.

Police said one of the cars was on the wrong side of State Highway 1, about 3km north of Amberley, when the collision happened about 6.20am.

Acting principal of Shirley Boys' High School Tim Grocott confirmed the 16-year-old male killed in the crash, Dexter Barham, was a former student at the school.

A current student at the school was also involved in the crash and was currently in hospital suffering from a head injury.

Grocott said he believed this student was on the mend.

Counselling and support was being offered to those students who may need it," Grocott said.

"We've spoken to students in years 12 and 13 this morning in an assembly."

"We've said that if anybody is struggling, is feeling upset, concerned or angry then they should go and see our counsellor."

The incident was "absolutely awful", Grocott said, and was "very upsetting" for the school community".

Brown's brother had posted on social media about his sister's death, writing "I would do to say I love you one more time, to hug you one more time".

"I will forever treasure the moments I spend with you and Dexter I love you guys soo much."

A friend of Rose had posted, calling her friend "young, wild, free spirited and so damn beautiful".

"You lived life at 1000kmph there was nothing you couldn't do, so strong willed."

One of Dexter's friends told the Herald he knew the Christchurch local from his time spent at the Washington Way Skate Park.

"I remember all the good times we had at the skate park together always having a good laugh and always going down the road to get lunch from McDonald's," the friend said.

"He was a amazing kid with a heart full of gold, he would always make you laugh and he always had a smile on his face."

Two men in the other vehicle received non-life threatening injuries in the crash and were receiving medical treatment.

A witness at the scene overheard a conversation between a police officer and a worker from Downer Group, in which the officer said the driver of the vehicle responsible for the crash was driving illegally.

The driver had their learners licence, the witness understood, and was driving without a passenger holding their full licence in the car.

Another witness who arrived at the scene soon after the crash said a ute and a white sports car had clearly collided, but a lorry was also pulled over to the side of the road.

"It happened on a bend going over a bit of a hill and they met at the top of it - so they were possibly overtaking in a stupid place. If so, that's a terrible place to overtake."

"I think the guy in the ute survived but he was in pretty bad condition - they choppered him to hospital."