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!"
"You could actually see, just by chance, down to the forest floor and there they were."
"If these guys went into the bush and I was not allowed to fish then I want the book thrown at them!"
Both became injured while lost in the bush for weeks.
They had been missing for 18 days in Kahurangi National Park.