State Highway Eight is closed by a chemical spill from a crashed truck, 10km south of the Lindis Pass Summit.
Police say the truck was carrying dangerous goods which are still being identified. The crash occurred at about 3.15am on Wednesday.
The road is likely to remain closed until midday.
Emergency services found a body in a burning car on SH8 at Cricklewood, near Fairlie, on Wednesday morning. The road is now open again.
State Highway 94, from Lower Hollyford to Milford Sound, is open again after overnight snow but the Transport Agency says chains must be carried.