State Highway 1 has reopened between Wellsford and Warkworth. It was closed for about four hours after a serious crash this afternoon.
Four people were hurt, one critically, when a car collided with a van in the Dome Valley.
Diversions were in place via Wayby Valley Rd and Kaipara Flats Rd South as the Serious Crash Unit investigated, but police began to lift cordons at 7.50pm.
Emergency services were called to the scene at 4.08pm.
Three people, including a woman who is believed to be pregnant, were trapped in the vehicles and had to be freed by fire crews.
Two people were flown to Auckland Hospital on Auckland's Westpac Rescue helicopters - one in a critical condition and the other with serious injuries. Another two, with moderate injuries, were taken to North Shore Hospital by road ambulance, St John Ambulance said.
Bill Calthrop, whose wife owns the Top of the Dome cafe said the crash happened about 275m north of the cafe.
"A truck has hit a pickup truck. The sound of the collision woke me up."
A pregnant women was trapped in one of the vehicles, he said.
"It's a very bad crash. It's going to be a long time before it's cleared."
Numerous ambulances and police cars were at the scene and a Westpac rescue chopper had landed in the car park opposite Kraack Rd, Calthrop said.
Northern fire service communications shift manager Scott Osmond said two trucks attended.
Two other people, who were not seriously hurt, were believed to have been in the vehicles.