Traffic has been affected near Hamilton this morning after what is believed to be a diesel spill.
Police said diesel, or another slippery substance, had been spilt on State Highway 1B between Hamilton and Taupiri.
Due to the spill several crashes have already been reported to police, and other motorists have reported finding it difficult keeping traction on some bends on the road.
No-one has been injured in any of these crashes, police said.
Rain through the area was also worsening the effect of the substance on the road, police said.