Fire Service crews were alerted just before 3am, and units from Roslyn and Lookout Pt brought the fire under control.
Lookout Pt Station Officer Keith Maydon said the fire was well advanced by the time crews arrived.
He was concerned about the safety of his firefighters because of a power pole next to the house but, fortunately, the fire followed the roof line and neither damaged the lines nor cut power to surrounding homes, and the fire was put out fairly quickly.
Later in the morning, a scene examination was being carried out and two detectives, a fire safety investigator and a photographer were at work at the site.
The brick and plaster two-storey house, which Detective Sergeant Chris Henderson, of Dunedin, said was unoccupied at the time of the fire, was badly damaged.
The house was on the corner of Aitken Pl and Glenpark Ave, and Det Sgt Henderson said police were keen to hear from anybody in the vicinity of those streets, Haig St and the surrounding area who saw anyone acting suspiciously.
"Police are treating it as suspicious until we determine what has been the cause of it." Police had no information on Saturday whether the house was usually occupied, and were trying to notify the owners.
A man was charged with arson and remanded in the secure unit at Wakari Hospital until April 24 after the alleged arson of another Glenpark Ave house late last month.
