Hundreds of litres of a caustic substance have spilt over the road near Takaka.
A Fire and Emergency spokesperson told Newshub sodium hydroxide - also known as caustic soda or lye - is running over Takaka Hill Highway after leaking from a truck.
They said there were about 6000 litres on the truck, and hundreds of litres are leeching onto the highway.
Police were called to the spill at 3:15pm on Wednesday and say it's covering both lanes of the highway on the Takaka side.
All motorists are advised to expect delays.
