Fire crews have spent most of the night fighting a "massive blaze" at a mill in the Thames-Coromandel district.
A Fire and Emergency NZ spokeswoman says crews were called to the fire, in Paeroa Kopu Rd, Matatoki, about 9.20pm.
Crews from Ngatea, Puriri, Paeroa and Hamilton attended.
A local resident who didn’t want to be named heard a large explosion at around 9pm, reports Stuff.
"I thought it sounded like gas canisters exploding," she says.
"I really felt for the fire fighters as they were battling not only the fire but winds of tornado strength."
A statement on the Matatoki Primary School facebook page said that the school has been closed for the day, due to the students safety.
It also said that State Highway 26 is closed between Kopu and Matatoki.