A St John spokesman said one person was being taken by helicopter to Dunedin Hospital with serious injuries.
They did not provide detail about the condition of the second patient.
Fire and Emergency New Zealand were also called to the scene.
Motorists have been asked to avoid the area.
Motorbike crash
Meanwhile another helicopter was called to a crash between a motorbike and a car near Alexandra this afternoon.
A police spokeswoman said they were called to the crash on Crawford Hills Rd, Galloway, at 2.48pm.
The crash happened about five minutes from Tiger Hill Rd.
A police spokesman later said a helicopter was sent to the scene and one person was taken to hospital.
Police did not have details about the seriousness of the person's injuries.