Motorists in Auckland are being warned to avoid a busy highway following a chemical spill from a truck.
Waipuna Rd has been closed near the intersection with Mt Wellington Highway as firefighters try to mop up the chemical.
"The chemical is a dye and the issue is with its collection and disposal as it cannot be flushed into the storm water system," police said.
Drivers are being warned to avoid the area, which is expected to be closed "into and possibly through the rush hour".
Mt Wellington Highway is not closed, but traffic attempting to turn into Waipuna "will no doubt cause backlogs", police said.
Signage would be put in place to warn drivers.
The spill occurred around 4.50am, Fire Service northern communications shift manager Jarron Phillips said.
It was not yet clear what caused the spill, but the truck had not been involved in a crash, he said.
Around 20 litres of a liquid dye had been spilled over a few hundred metres of road.
No injuries had been reported, but the truck driver had been de-contaminated.
A road clean up crew had also been de-contaminated, Mr Phillips said.
Two Fire Service hazardous materials units were at the scene, where a full de-contamination tent has been set up, along with another three fire crews to deal with the spill.
It was expected to take "some time", he said.
