Updated 5.52pm: Police have confirmed a woman has died following a two-car crash south of Rotorua on State Highway 5.

One lane is now open between Old Taupo Road and the State Highway 30 intersection.

State Highway 5, by Waipa State Mill Road, is currently blocked. Photo: File.

Police say a woman from one wehicle died at the scene and a baby from that vehicle has been taken to Rotorua Hospital. He is believed not to be injured at this stage.

Two men from the second vehicle have been taken to Rotorua Hospital with moderate injuries.

An investigation into the cause of the crash is underway. The Rotorua-bound lane is now reopen and the Taupo-bound lane is expected to open shortly.

Earlier:

Emergency services are at the scene, near Waipa State Mill Road, and motorists are being urged to avoid the area as traffic is building.

The fire service has confirmed there has been one fatality, while three other people were trapped, with one critically injured.

The public are being advised to take alternative routes and to be patient.

This closure is understood to be affecting all traffic between Rotorua and Taupo on SH5 and all traffic between Rotorua and Tokoroa on SH30, and there is already considerable congestion.

Any motorists intending to use these routes are advised to delay their trips, or use the longer alternative route from Rotorua across the the Mamaku Range to pick up SH1, and the reverse if travelling to Rotorua from Taupo or Tokoroa.

Traffic already on SH5 heading into Rotorua will be diverted off at Waikiti Valley.

The Transport Agency have also advised that a detour via SH5, SH1 and SH30 is in place, however it will add approximately one-and-a-half hours to normal travel time.