A truck and trailer unit has flipped in South Canterbury, blocking State Highway 1 this morning.
Fire and Emergency southern shift communications manager Andrew Norris says the crash happened about 4.40am south of Ashburton.
The highway between Ashburton and Rangitata is now closed and a detour is in place between Winslow Willowby Rd and Long Beach Rd.
No one was hurt and the driver was already out of the overturned cab by the time fire crews arrived.
It was unclear what the truck was carrying but the cargo did not pose any danger, said Norris.