"Two men in the other vehicle received non-life threatening injuries and are receiving medical treatment," a spokeswoman said.
"One of the vehicles involved in the crash has crossed the centre line."
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."
He had overheard a police officer saying the teenage driver of the white car did not have a licence, he said.
"I think the guy in the ute survived but he was in pretty bad condition - they choppered him to hospital."
A St John spokesman said two of those hurt were seriously injured and another had moderate injuries.
The deaths follow a horror weekend on New Zealand roads last week, when nine people were killed.
Five people died on Saturday, March 10, in three different crashes. The next day, three people died during a police pursuit - including an innocent motorist in one of the vehicles.
An elderly woman struck by a vehicle in Tauranga, on Friday, March 9, died of her injuries in hospital.
The Serious Crash Unit is investigating the Amberley crash.
The crash brings New Zealand's road toll for March to 21, after a person was killed in a crash in Reporoa near Taupō last night.
By Friday, 86 people had been killed on our roads this year, compared to 74 this time last year.
