A police spokeswoman said a two-vehicle crash occurred on the Gibbston Valley highway about 8.45pm.
Two fire crews from Arrowtown and Frankton are in attendance.
A Fire Emergency New Zealand spokeswoman said the vehicles involved were a car and a transport truck.
St John sent out a media alert saying one person had died.
Police also confirmed one person was killed in the crash.
The crash has caused State Highway 6 to close between Pearson Rd in Cromwell, to Crown Range Rd at Arrow Junction.
A detour over Crown Range is in place and NZTA are advising motorists to allow for the extra time the drive will take.
The Serious Crash Unit and the Commercial Vehicle Safety Team are attending.
Diversions are being put in place and motorists are asked to avoid the area if possible.
