Fire and Emergency New Zealand attended a fire in the house in Burrow St at 7.54am on Thursday.
One person was taken to Southland Hospital with moderate injuries.
Fenz Southland assistant area commander Deane Chalmers said the house was "completely destroyed".
Investigators were still assessing the
cause of the fire, Mr Chalmers said.
"The fire is not being treated as suspicious and they believed it started somewhere in the kitchen area."
Early indications suggested the house did not have smoke alarms, he said.
"This just highlights the importance of having fire alarms at houses to secure the safety of its occupants so they can get out quicker.