The accidents in Central Otago happened less than 10 hours apart, and in both cases, bad weather prevented the crash victims being airlifted to Dunedin Hospital by helicopter, so they were taken by ambulance. One vehicle hit a large rock near Alexandra and the another collided with a tree at Millers Flat.
Three people were killed in Gisborne - Dylan Kingi (28), Holly Gunn (25) and Peter Bunyan (27) - after trying to evade police on Saturday night, a man was killed in Mangere after a car hit a power pole early yesterday, and a motorcyclist died in hospital yesterday after a collision with a car near Rotorua on Saturday.
Eleven people died last July on New Zealand roads but that figure has already been exceeded with 15 deaths by last night.
The total number killed this year is 156, compared with 150 at the same time in 2011.
Those accidents follow a horrific head-on collision with a truck last week in the central North Island that killed four young Argentine men.
Acting road policing manager Inspector Rob Morgan said the crashes - particularly the ones with multiple victims - were the result of poor decision-making, speed and alcohol.
He called on passengers to take some responsibility.
His message was: "Just emphasise the need to be really careful when you jump in the car with someone else.
"That person is in control of your safety."
Senior Constable Mike Colligan. of Alexandra, said two Dunedin women were the occupants of a Honda Accord which was travelling to Alexandra on State Highway 8 on Saturday about 4pm.
"The vehicle left the road and has hit a rock, launched into the air and then come to a halt after hitting another, larger rock, splitting the rock and ending up with the vehicle straddling a culvert."
A 17-year-old woman was driving and a 59-year-old was the passenger, he said. Both were taken to Dunstan Hospital at Clyde and the older woman was transferred to Dunedin Hospital, where she was in a stable condition in the intensive care unit last night. No further details were available about the driver's condition.
Snr Const Colligan said a doctor who was driving on the road was one of the first people at the accident scene, followed quickly by an ambulance which had been heading to Dunedin to collect a patient and bring them back to Central Otago, and another ambulance which was transferring a patient to Dunedin.
"It was amazing to think there were medical staff and two ambulances on the spot so quickly, by sheer coincidence, followed of course by the ambulance which had been called. We were grateful for all the assistance."
Alexandra Fire Brigade volunteers used the jaws of life to cut the women from the vehicle.
Snr Const Colligan said the crash was being investigated.
Speed and alcohol were not factors. The road was clear, with no ice.
Sergeant Andy Reed, of Roxburgh, said an 18-year-old man in a Toyota Hilux was travelling south on State Highway 8, just north of Millers Flat when his vehicle left the road about 1.35am yesterday.
"He appears to have gone off on a gentle right-hand curve, gone through a fence and then hit a large, dead macrocarpa tree."
The man received chest and head injuries and was in a stable but serious condition in Dunedin Hospital's intensive care unit last night.
The road was wet at the time, but not icy, Sgt Reed said.
Police were still investigating the crash but speed did not appear to have been a factor.
