A truck has caught fire near Kaikōura and forced the closure of State Highway 1 this afternoon.

Video from the blaze shows smoke billowing into the air with the truck pulled over to the side of the road.

Photos show debris from the trailer snaking along the road as bystanders look on.

James Dixon, who was behind the truck, told 1News something caught fire on the trailer while it was driving.

“Many cars passing by were trying to flag it to the driver,” he said.

He understands the truck drove “a few kilometres before realising” it was on fire.

He said its cargo was “random things” like inflatable plastic kid balls, Frisbees, Hula hoops, and ironing boards.

After pulling over, the trailer was disengaged, and the driver moved the truck about 50 meters up the road, he said.

“Motorists are advised to avoid the area, seek alternate routes and expect delays,” a police spokesperson said.