Whangārei senior fire officer Paul Ballentine said the house was extensively damaged, but the residents of the house were in town shopping when it caught fire.
He acknowledged the support of the police and also Northpower in cutting electricity to the house.
Fire and Emergency were alerted to the blaze at about 12:15pm.
Two police officers were operating a cordon, directing traffic away from the house, as large plumes of smoke came from the weatherboard house.
A few neighbours who went out into the street to see the fire appear to have been driven back inside by the persistent rain.