At least one person is seriously injured following a two-car crash on State Highway 2 in Clareville, near Carterton in the Wairarapa.
Police said they were called about 2.45pm after the two cars collided.
They said one person has serious injuries, and it was too soon to say whether anyone else had been injured.
They did not know how many people were in the vehicles at the time of the crash.
The police said diversions are in place on SH2 between Hughes Line and East Taratahi Road.
The Serious Crash Unit is at the scene and the road is likely to be closed for some time.