State Highway 5 is open following a fatal three car crash south of Rotorua.

Investigations are underway into the cause of the crash, which happened about 4.45pm at Waumangu.

Six people have been injured and one person is dead after a three car crash yesterday afternoon. Supplied photos.

'One person has died, two are in a critical condition and one is seriously injured,” says a statement from police.

'Three others have suffered minor to moderate injuries.”

The Tauranga-based Trustpower TECT Rescue Helicopter and Taupo's Greenlea Rescue Helicopter were called into to transport the injured patients to hospital.

Tauranga pilot Liam Brettkelly says two cars collided head-on and another was also involved.

'The Trustpower TECT Rescue Helicopter flew a 58-year-old Rotorua woman to Waikato Hospital in a serious condition, she had pelvic, chest and abdominal injuries.

'The woman's husband was flown to Waikato Hospital by the Greenlea Rescue Helicopter and the remaining victims were taken to Rotorua Hospital by St John ambulance.”

The serious crash unit is investigating.

Anyone who may have witnessed the crash or been driving in the area at the time is asked to contact Rotorua Police on (07) 349 9400.

Alternatively, information can be left anonymously via the Crimestoppers 0800 555 111 line.