One person has died after a serious crash on State Highway 1 near Waiouru.
A witness to the horror crash in Ruapehu District had to smash a car window to rescue people - including an infant - from the wreckage.
At least seven people were were injured in the two-car collision, which closed State Highway 1 south of Waiouru.
Police were called to SH1 in the Waiouru Military Area, about 11.45am today.
A St John spokeswoman said earlier one person was in in a critical condition, two in a serious condition, and four had moderate injuries.
Crash witness Alex Campbell said he was driving north behind a car when it tried to overtake a truck on a blind corner.
"It went head-on into a car coming the other direction," Campbell told the Herald.
"I got out and went over. My adrenaline was pumping really hard and all I was thinking was 'how can I help the people in this situation and get this family out as quickly as possible'.
"I helped the driver out of his seat. I then proceeded to help his family out of the vehicle.
"There were two adults in the back, a mother and possibly grandmother.
"I had to pin the passenger front door open, bend the top of it and break the window to get an infant girl out of there."
Campbell said another child and baby were also removed from the car.
He said at least two people were in the other vehicle.
"The passenger was trapped inside, so we had to wait for about 20 minutes for the ambulance to come with the jaws of life."
Campbell said the front of both vehicles was caved in.
He said the truck appeared to have continued on and was not involved in the crash.
A rescue helicopter had been sent from Palmerston North.
The road was closed and motorists were advised to avoid the area.
The Serious Crash Unit had also been advised.
Two killed in fiery crash near Oamaru
The crash near Waiouru follows a double fatal near Oamaru late last night.
A third person was injured in the single-vehicle crash at the intersection of TY Duncan and Shortland Rds, Oamaru North, about 11pm on Wednesday.
Fire crews found a car alight and two bodies inside.
Detective Sergeant Hannah Booth, of Oamaru, said the cause of the crash was being investigated.
She also confirmed to the Otago Daily Times the two people killed in the crash were from Oamaru.
She said the 18-year-old driver was in Dunedin Hospital in a serious but stable condition.
Further details about the two people killed are expected today.
"Their next of kin have yet to be notified. We are not going to be releasing any details about them at this stage," Booth said.
TY Duncan Rd is a rural road off State Highway 1, between the highway and the coast.
Two fire crews put out the blaze and the road has been reopened.