The cause of the last night's fire at the Free Wesleyan Church of Tonga in Raumanga, Whangārei is still unknown.
Fire investigators visited the property this morning after multiple crews attended the blaze about 10pm, which had engulfed the church's roof.
Most of the damage had been inflicted to the upper section of the tall church building. It was fortunate the fire did not spread to nearby trees or buildings as the church sits beside a hall, a playcentre and a house.
Siulolo Ahio, who lives at the house next to the church with her two children and husband who is the church's minister, said she first discovered the fire when she could hear an unusual rattling sound from the church.