Hato Hone St John said two ambulances were at the scene.
The Serious Crash Unit has been advised.
NZ Transport Agency Waka Kotahi said the crash was blocking SH7 in North Canterbury, just south of the turnoff to Hanmer Springs.
Emergency services are responding and road users are advised to delay travel in the area or use an alternative route.
People are asked to follow the directions of emergency services at the crash site.
State Highway 7/Mouse Point Rd is closed in both directions and diversions are in place.
NZTA contractors are travelling to assist.
More to come.
Ben Tomsett is a multimedia journalist based in Dunedin. He joined the Herald in 2023.