Police say a diesel spill on State Highway 29 has caused problems for traffic travelling through the Kaimai Ranges between Hamilton and the Bay of Plenty.
On Friday morning, the spill extended for about 4km in west-bound lanes spanning both sides of the summit.
Signage was in place, but police say some drivers appeared to be ignoring the danger.
They asked motorists to take extreme care, particularly on the downhill, Hamilton side.
