Emergency services continue to work at the scene of the serious crash on State Highway 5, near Mamaku, about 20 minutes north of Rotorua, where a bus has rolled.
It is believed more than 20 people were on board the bus at the time of the crash.
A number of those passengers are reported to have been injured.
Patients are being transported to both Waikato and Rotorua.
Police can advise there have been fatalities in the crash, however the number cannot yet be confirmed.
The Serious Crash Unit and the Commercial Vehicle Safety Team are attending the scene alongside other Police staff.
The road is expected to remain closed for some time, and motorists are asked to avoid the area and delay travel.
More information will be released as it becomes available.
Issued by Police Media Centre
A media stand-up will be held at Rotorua Police Station on Fenton Street at 5pm. Media are asked to arrive five minutes beforehand to allow for set-up.