Two people have been critically injured and another is in serious condition following a crash on a Bay of Plenty highway.

Emergency services were called to the single vehicle crash on State Highway 38, near Murupara, just after 7am.

Northern Fire Communications shift manager Jaron Philips says initial reports were than one person had been thrown from the vehicle when it hit the roadside.

'Fire crews are working with cutting gear to free one patient who is heavily trapped in the car.”

Two helicopters have been called to the scene about 2km towards Rotorua from Murupara.

Diversions were being put in place via Pekepeke Road.