Forensic scientists have been called in to help police and fire investigators determine how the man died on Sunday morning.
Fire crews converged on the property at the corner of Braemar and Tyne Sts shortly after 8.30am, following reports of smoke coming from the roof of the house.
Upon entry they found a man unconscious. He could not be revived and St John said he died at the scene.
Senior Sergeant Craig Dinnissen, of Dunedin, said the cause of death remained unexplained.
Forensic specialists from Environmental Science and Research would be arriving to help detectives and fire investigators, he said yesterday.
It is unclear whether the man died before or after the fire started.
It is understood while the death of the retired man is unexplained, it is not thought to be suspicious.
At the scene yesterday morning was Steven Cooper, a grandson of the man.
His grandfather was a keen golfer who loved his family, he said.
"All of us kids have been through here.
"My mother, all her sisters, her brothers, all raised in this house.
"He always had time for his family.
"It's a sad way to lose him.''
A woman who lives next door, and who asked not to be named, fought back tears as she described a man who was a friendly face over her fence for more than half a century.
"He was a neighbour of about 54 years ... and he was a lovely neighbour and friend.
"I'm still quite emotional about it.
"It's just sad to think that you get to our age and it ends like that.''
