A young man is in a stable but serious condition in Auckland City Hospital after his car crashed on Baylys Coast Rd, near Dargaville.
The 18-year-old, believed to be on a working holiday from the United Kingdom, was the sole occupant in the car that spun off the road and rolled at around 2.45pm on Saturday.
The seriously injured driver was airlifted to Whangarei Hospital by Northland Rescue Helicopter, then transferred to Auckland.
An update on his condition was not available at edition time.
With another day to go before Northland's highways were expected to get busy again with Easter holiday traffic, Whangarei Police asked that people drive to the conditions.
Senior Sergeant Darren Sullivan said police hoped motorists would drive with patience and consideration, "to ensure everyone gets home safely".
Yesterday saw the heaviest traffic buildup between Wellsford and Puhoi between 2pm and 5.30pm.
Today two-way traffic was expected to get busy north and south of Whangarei, with heavy congestion predicted mainly in southbound lanes south of Wellsford, from 10am to 7.30pm.