Palmerston Volunteer Fire Brigade Chief Fire Officer Gary Johnston said no-one home had been at the time of the fire, which was reported by neighbours who heard smoke alarms ringing about 12.20pm yesterday.
When the brigade arrived they found the Stronsa St blaze well involved.
Firefighters using breathing apparatus made entry and were able to knock the fire back reasonably quickly.
The blaze left half the home gutted, with a "huge amount" of smoke and heat damage to the rest of it.
The mother of one of the homeowners told the Otago Daily Times, the father and the five children who lived in the house had been unharmed.
The youngest was 4 years old.
A cat and a dog had died in the blaze, she said.
A Fire and Emergency New Zealand spokesman said crews from Palmerston and Waikouaiti stations were initially dispatched, but due to the remote location and the nature of the reports further appliances from Waitati, Willowbank and Dunedin Central were also sent to the scene.
A fire investigator would attend as the cause of the fire was unknown.
The fire had not been flagged as suspicious, the spokesman said.
— additional reporting Hamish MacLean.