State Highway 10 near Kerikeri is likely to be closed well into the night following a serious crash near the Kerikeri crossroads just after 5pm.
A mother and two young children in one car, and the elderly male driver of the other, were all injured. Their condition is not yet known.
At least two patients were expected to be airlifted to Whangarei Hospital by the Northland Electricity Rescue Helicopter, which landed in the grounds of Westmount College.
The crash occurred on SH10, near Blue Gum Lane and about 2km north of the Kerikeri crossroads.
The highway is closed at the Kerikeri roundabout and Waimate North Rd.
It will not be reopened until the police Serious Crash Unit arrives and conducts a thorough scene investigation.
Police are still investigating the cause. It is thought the driver of one vehicle lost control and crossed the centreline.