The occupants, a woman and her young son, were out at the time so it was "very fortunate" neighbours spotted the fire.
They turned off the power, broke a ranch slider to gain access, and fought the flames with a garden hose until Kāeo Fire Brigade arrived.
They were backed up by crews from Mangonui and Kerikeri.
It appeared the fire had started from a wood burner, which had ignited a bucket of firewood before spreading to a couch and then up a wall.
The home was fitted with smoke alarms which were sounding when firefighters arrived.