The accident happened on the Kaipara Coast Highway.
A man has been seriously hurt after the car he was driving crashed into a sheep on a rural highway, north-west of Auckland.
The incident has closed the road - Kaipara Coast Highway - between Barr and West Coast roads, a police spokeswoman said.
Diversions are in place as the police Serious Crash Unit investigates.
A St John ambulance spokeswoman said a man, the vehicle's sole occupant, was seriously injured and would be taken to hospital by helicopter.
NZTA said drivers in the area should follow the directions of emergency services, avoid the area or delay their journey if possible.
A fire crew is at the scene helping police direct traffic.
The crash happened about 1km south of the intersection with West Coast Rd around 6.50pm, a Fire and Emergency New Zealand spokesman said.
No information was available about whether the sheep was injured or killed.
The Kaipara Coast Highway is also known as State Highway 16.
'He has disregarded our voice and continued with this divisive kaupapa.'