Two people are in critical condition following a crash in the Western Bay of Plenty.

Emergency services were called to the single-vehicle crash on Hot Spring Rd at Tahawai, near Katikati, at 9.15pm.

Hato Hone St John says they responded with two ambulances, two helicopters, and one rapid response unit to the scene.

"Our crews assessed and treated two patients who were airlifted to Tauranga hospital in a critical condition."

"Two people received critical injuries when the vehicle they were in left the road and flipped down a bank into a paddock," says a police spokesperson in a statement to SunLive.

"The vehicle came to rest about 200 metres down a slope."

Police say a passenger in the vehicle was ejected during the crash.

"A rescue helicopter from Ardmore and another from Tauranga transported both two occupants to hospital.

"The Serious Crash Unit was notified and an investigation into the cause of the crash is ongoing."