A light truck carrying scaffolding has crashed on SH73 Otira Highway, Arthurs Pass National Park at about 10am this morning.
The crash occurred between Settlement Road and West Coast Road.
It appears that the truck has hit a rock face after clipping another vehicle from behind.
The driver was taken to Christchurch Hospital by helicopter in a serious condition.
No one else was injured.
The road will be closed for approximately two hours, while Police investigate.
Motorists are asked to avoid the area and expect delays.