A person is in a critical condition after their car crashed into a tree on State Highway One north of Warkworth.
Emergency services received the call just before 7:30am.
It appears there was only one person in the car that crashed just north of the intersection with Kaipara Flats Road.
The driver has been flown to hospital.
Traffic is being diverted off the affected part of State Highway One and police have set up a detour through to State Highway 16.