The fire started in a forestry block
The destruction has delayed roadworks scheduled in Motueka.
There is minimal risk to the community following the incident, police say.
The Motueka Sunday Market asked stallholders to be vaccinated and wear masks. They left to start their own market where they don't obey the rules.
It's covering both lanes of the highway.
Multiple emergency services vehicles are at the scene.
The Takaka firm is selling the pants, featuring an image of the Hindu deity Lord, for $15.
Others are reported to have sustained injuries.
"It really is amazing what you can do when your life depends on it!"