Emergency services were first alerted about the blaze about 9.30am. Fire crews and police responded to the fire at a Crawford St house in the suburb of Glengarry.
Resident Dylan Thian said he was at home when he saw black smoke coming from the nearby property.
"I heard the crackling, the banging. I just live around the corner from it, so I [have] seen it all from my house.
"I came down just to make sure that no-one was burning rubbish and it turned out to be the house was up in flames."
Mr Thian said when he arrived he could only see a heavy black smoke and the roof well alight.
"I couldn’t get in the front, so I went around the back and I was yelling out and couldn’t hear anybody or anything.
"It was just roaring flames and crackling."
Mr Thian said he helped the neighbours to get their dog out of their house and then told officers what he saw.
A spokeswoman for Fire and Emergency New Zealand said four appliances from Invercargill and Kingswell stations attended and the fire was quickly contained.
There was no-one in the property at the time.
