A truck carrying hazardous chemicals has crashed on the Whangamoas and is "hanging" over the edge of the road.
The state highway - the main route to Blenheim, is closed at Hira while a heavy tow is arranged.
A police spokesperson says they were called about 4.40am on Thursday after a truck hauling hazardous chemicals went off the road and collided with a barrier, between Central Road and Hori Bay Road.
There are no reported injuries and no damage to the vehicle’s load.
Due to the position of the truck, which is hanging over the edge of the road, both lanes have been closed while a heavy tow is arranged.
The road is expected to be closed for some time and the only alternative route is through St Arnaud. Motorists are advised to expect delays and check NZTA’s Journey Planner website for latest road conditions.
