The house was empty but Mr Ashwell said a young English couple had moved in several months ago and were living there with their two young children.
Neighbours in dressing gowns and slippers had gathered in the street to watch two fire trucks and firefighters in action.
Aimee-Lee O'Shea, staying in the street on holiday, said the fire started at the front of the house and it went up fast.
Senior station officer Bryce Coneybeer said all the trees at the front of the house had caught fire, but nearby houses were safe.
He thought the owners of the house were at work, and the police were trying to contact them. Police and fire investigators would be looking into the cause of the blaze," Mr Coneybeer said.
Firefighters used water and foam, and wore breathing apparatus to work amid the smoke.