Two fire crews were called to the property on Gayhurst Rd in Dallington just before midnight on Sunday.
Fire and Emergency NZ received reports of trees on fire - which had then spread to the house.
Authorities said the house appears to have been abandoned and there were no reports of injuries.
The 100 sq m single-storey house was well-ablaze when crews arrived.
Fire and Emergency said the fire was being treated as suspicious because the house was unoccupied.
The fire was put out just after 3am.
A fire investigator will be back at the scene early on Monday.