Both southbound lanes on the Hawke's Bay Expressway were covered with diesel after a spill on Tuesday night.
Emergency services were called to State Highway 2, near Frimley, about 9.15pm on Tuesday.
A Fire and Emergency New Zealand spokesman said a 1000 litre container came off a vehicle.
Police said the spill covered both southbound lanes of the Expressway. Two fire trucks were called to the scene.
