The petrol station has been evacuated as a precaution and the pumps have been shut down.
The fire is well involved and police are assisting with traffic management, a police statement said.
The sole-occupant is out of the building and is not reported to be injured.
Large plumes of smoke can be seen coming from the commercial building. Photo / Tori BramleyImages are of the fire are emerging showing large plumes of smoking coming from the building.
The fire is at a building next to the Z petrol station in Levin. Photo / David GrowcottThe road is closed between Seddon and SH1 and diversions are in place.