Police confirm there have been fatalities after a bus rolled on State Highway 5 west of Rotorua.
More than 20 people are believed to have been on board when the bus crashed on Wednesday morning in bad conditions, leaving the bus on its side.
As many as six could be dead and another six have been transported to hospital.
Liang Zhi, a diplomat from the Chinese Embassy in New Zealand, told The Associated Press the bus was carrying Chinese tourists.
A heavy lifting crane is at the scene, and five helicopters and five ambulances have been dispatched by St John.
"We can confirm one patient in serious condition and one patient in moderate condition have been airlifted to Waikato Hospital; one patient in moderate condition has been airlifted to Tauranga Hospital; three patients in moderate to minor condition have been transported by road to Rotorua Hospital; and 15 patients have been transported to a secondary triage area for further assessment," a St John spokesperson says.
"St John is continuing to manage patients and will support and debrief our responders in the following days."
Fire and Emergency says four of its crews are responding.
The serious crash unit and the commercial vehicle safety team are attending the scene alongside other police staff.
"The road is closed, and diversions will be in place," a police spokesperson says. "Motorists are advised to avoid the area."
More to come.