The fire service was called to the blaze on Kaponga St in Mamaku - near Rotorua - about 1.15am today.
The single-storey building, which is used as a church, was "well involved in fire" when firefighters arrived at the scene.
Crews from around the region were called and between 24 and 30 firefighters attended.
A St John spokeswoman said one patient with moderate injuries was taken to Rotorua Hospital.
A fire service spokeswoman said one person - a member of the public - was seen to by ambulance.
The person was suffering from smoke inhalation, she said.
Mamaku resident Shane Hutchinson said the church had been there for years.
"It was a pretty church, I live a street over and everybody at the school was telling me so I thought I'd come and have a nosy."
Mr Hutchinson works at Mamaku School and said most people there were feeling "very sad" about the fire.
Another Mamaku resident who did not want to be named said it was a "great shame".
"It was an old pretty church up on a hill... [I'm] feeling quite sad," he said.