A truck carrying toxic chemicals has caught fire on the Lewis Pass Road on State Highway 7, closing the road to all traffic.
Fire engines from Hanmer Springs and Christchurch were sent to the blaze near the Engineers Camp, about 22km south of the Lewis Pass, at 8.20am on Friday.
The road, which is known as the alternative South Island state highway, has been in heavy use since an earthquake in November last year damaged the coastal State Highway 1 route.
Crews from Christchurch included a hazardous materials team.
A fire communications spokesman could not confirm what chemicals the truck was carrying, but said the road would be closed for "some time".
"We have no reports of casualties or injuries at this point," he said.
The road had only reopened on Thursday after it was closed due to heavy snow the previous day.
Road blocks were in place at the Hanmer Springs turn-off and at Springs Junction, a police spokesman said.
"There are no diversions available and motorists are asked to delay travel in the area," he said.
Rider injured in collision
A second major highway in the South Island was closed for about an hour on Friday after a motorcyclist was seriously injured.
Police say the incident happened on Cobden Bridge in Greymouth after a car and motorbike collided. The rider was taken to hospital.
Other alpine passes are openm but chains are needed to cope with icy conditions.
