A driver whose truck and trailer crashed near Timaru has died.
Police said no other vehicles were involved in the crash which happened at 8.30am on the Orari-Rangitata Highway.
The crash closed part of SH1 north of Timaru and traffic was diverted.
In a second serious truck crash this morning, two trucks collided on State Highway 3 near Inglewood, spilling hazardous chemicals on the road.
Emergency services were called at 8.15am to the scene, at the state highway's intersection with Lower Dudley Road.
One of the vehicles was carrying drums containing dangerous chemicals, and several of the drums fell on the road and split.
SH3 was closed from Inglewood to Norfolk while a Fire Service hazardous material unit cleaned up the spill, and traffic was being diverted.
No one was injured.
Emergency services also attended several oil spills on and near SH3 at Awahuri, between Palmerston North and Fielding. The cause of spills was unclear.