A police spokesman confirmed they were responding to a “serious” crash in the Hurunui district.
“Initial indications suggest there are serious injuries,” he said.
“State Highway 1/Parnassus Rd is closed just south of Macmillan Rd, and motorists are asked to take alternate routes.”
A police spokesman later confirmed someone had died in the crash. The Serious Crash Unit was on the scene investigating.
The road was likely to remain closed for some time, the spokesman said.
A spokesman for St John Ambulance said they sent three helicopters, four ambulances and one operations manager to the scene.