The car reportedly caught fire after the crash, but emergency services managed to get the occupants out.
Emergency services were called to the scene on Whangarei-Dargaville Highway about 1.50am.
All three injured people were taken to Northland Base Hospital - two in a serious condition and one in a moderate condition.
The Matamata crash was the second fatal incident on New Zealand roads in two days.
Haydn David Clark, 20, from Drury, Jocelyn (Anne) Fielder, 64, and her husband Ian Fielder, 66, were killed in a smash near the Kopu Bridge in the Coromandel on Thursday night.
Clark's father, 54-year-old Jim Clark, the sole survivor, was cut from the wreck and taken to Middlemore Hospital in a critical condition. He remains in hospital.
Police say Haydn Clark was driving a stolen ute which crossed the centre line and collided with the Fielders' car.
He was facing methamphetamine charges and was on bail, including a 24-hour curfew order.
The Fielders' neighbour said the couple had been on their way home from a friend's place, where they had dinner every Thursday, when the crash happened last night.
"It was a little ritual they had," he said.
The neighbour said he was heartbroken at the deaths of the couple, who he described as "fun-loving, friendly" people.
"I couldn't believe it. I still can't believe it.
"It's just wrong."
