He was flown to Whangarei Hospital in a critical condition by the Northland Electricity Rescue Helicopter.
Police requested a blood alcohol sample be taken.
Other firefighters cleared oil, battery acid and debris from the road - along with what a witness described as a large number of paua that fell out of the car when a member of the public went to help the driver.
A police spokesman said the driver of one of the vehicles was believed to have tried to avoid the other.
A family in the vehicle taking the evasive action had been returning home after attending a fifth birthday party in Kaitaia.
A female passenger was admitted to Kaitaia Hospital with a suspected ruptured spleen, while three children, aged 3, 8 and 13, were taken to the hospital for a check-up. Two were reportedly treated for shock at the scene by St John personnel.
Nine hours before the Awanui crash, the rescue helicopter airlifted a 61-year-old Kerikeri man to Whangarei after he crashed twice within 500m.
The first crash, in which no one was injured, occurred as the man was turning right into SH10 at Pakaraka junction, colliding with a car heading south on SH1.
In an apparent attempt to flee the scene, the man continued driving up SH10, losing control at the first bend, demolishing a sign and a fence before hitting a tree.
It took firefighters from Kerikeri, Kawakawa and Kaikohe 40 minutes to cut him free.
Meanwhile, the only occupant of a white van was trapped behind the wheel for about 90 minutes after crashing in McCathie Rd, Ruakaka, about 11.30am yesterday.
The middle-aged woman with suspected significant injuries was freed by paramedics and fire service personnel shortly after 1pm.
Rob Hislop, who saw the crash, said the van crossed the centre line of McCathie Rd, ploughed along a fence and culvert on the opposite side and hit the edge of a raised driveway crossing the culvert.
Several large cabbage trees were thrown aside by the van's trajectory, just missing Mr Hislop's ute as he headed towards the highway.
He had approached the crash site expecting "something not very healthy", but was surprised to find the driver conscious and alert.
Ambulance staff wrapped flat fire hoses around the woman to steady her as they cut the driver's side door from her vehicle.
Officer in charge at the scene Senior Constable Martin Geddes ruled out speed as a factor in the accident, identifying potential causes as driver fatigue, alcohol or a fault with the vehicle.
No other vehicle was involved.
