Police are investigating suspicious fires in Patea on Christmas night and in the early morning of the following day.
Patea firefighters were called to a fire burning under a classroom at St Joseph's Convent School at 10.19pm on December 25, Chief Fire Officer Grant Hurley said.
It "took a bit of putting out", but the classroom suffered only smoke damage.
Firefighters were called again at 5.17 the next morning, to find a fire burning under St George's Anglican Church, a Category 1 historic building registered with Heritage New Zealand.
It was extinguished.
Both fires are suspicious, and police are investigating.
"It was two very good saves by the Patea Fire Brigade," Mr Hurley said.