A Tauranga fire investigator says a working fire alarm system has saved a historic Te Puke church from burning down.
A Northern Fire Communications spokesman said firefighters were called to a small fire in an exterior air conditioning unit at St John the Baptist Church on Jocelyn St about 3am.
Bay of Plenty Coast fire inspector Jon Rewi said a fire alarm system inside the church which had smoke detectors alerted the fire brigade of the blaze before it got out of hand.
"That saved the inside of the church," Rewi said.
"That church is a historic building that could have been catastrophic if we hadn't been alerted at that time."