The Remutaka Hill Rd section of State Highway 2 near Wellington is closed due to a car fire.
Fire and Emergency said they were called to the car fire just after 12pm, which has now spread into surrounding scrub.
Crews, including a helicopter, are currently working on putting the fire out, which has spread up the hill about 500m².
Video footage captured by a passing motorist shows a the car park on the side of the highway completely engulfed in flames, and large plumes of smoke rising into the air.
Flames can also be seen spreading up the bank beside the vehicle.
NZ Transport Agency is advising motorists to delay travel, otherwise all essential travel should detour via Pahiatua, which will add 3.5 hours to your journey.
The road is likely to remain closed for at least two hours, it said.