One person is trapped and another has been thrown from a car in a crash on the Gibbston Highway near the Crown Range on Monday afternoon.
One person is in a critical condition, one in a serious condtion, while two others have moderate injuries.
Emergency services, including a helicopter, are on the way to the scene.
Police say the road is currently blocked and may be for some time.
They ask motorists to avoid the area and plan for delays.
Newshub.