A 50-year-old woman is in serious condition after a collision with a fully loaded concrete truck on State Highway 1 south of Whangarei.
The One Tree Point resident was taken to Whangarei Hospital by ambulance but when her condition deteriorated, she was flown to Auckland by the Northland Rescue helicopter.
Highway patrol Sergeant Lance Goulsbro said the crash, just after 9am yesterday, happened during a passing manoeuvre in the northbound lanes on Lookout Hill.
Initial police investigations revealed a car travelling north in the outside passing lane was clipped by the woman's vehicle, forcing it into the path of the oncoming concrete truck.
Tyre marks could be seen on the road where the truck veered off the road and into a ditch, where it remained upright.
Mr Goulsbro said the woman had to be cut from the vehicle by firefighters.
The male driver and sole occupant in the other northbound car was able to drive away uninjured. The truck driver was shaken but not injured.
A tow truck hooked up to the side of the concrete truck and gently pulled the rig back onto the road.
While getting the vehicles cleared SH1, was temporarily closed, causing traffic to tail back to the Maunu Rd intersection with Western Hills Drive.
It cleared slowly once both lanes were reopened about 11.30am.