Fire services were called to the fire which gutted a bedroom, the hallway and part of the ceiling of the Richardson St house about 10.27pm.
Fire safety officer Barry Gibson, of Dunedin, said the fire began in a bedroom in the house and appeared to have started accidentally.
He had yet to complete his investigation into the exact cause of the fire.
"What I can say is that we are not considering it was suspicious."
The rental property was occupied by an 18-year-old girl, who was released from Dunedin Hospital yesterday after being treated for burns to her legs, a 58-year-old man and his 3-year-old son.
The man declined to give a full interview or be named yesterday, but said he was just grateful "we all got out OK. That's the main thing."
He was not sure what would happen now in terms of their accommodation, but said aside from the one bedroom and the hallway, the house was still intact.
Yesterday, neighbours and friends helped the occupants of the house, providing clean clothing and food for them.
