Mr Stewart's death comes several years after another tenant's body remained undiscovered for some time in the same flat and it is the third such discovery at Wellington City Council-owned flats to be reported in recent years.
In 2009 Wiremu Whakaue, 68, died in the same flat that Mr Stewart was living in when he died.
His body was not discovered until March 2010.
Michael Clark, 88, was found dead in his council-owned flat in Newtown in August 2011 - he had lived there for 30 years.
His body is thought to have been undiscovered for more than a year.
A woman, who wished to remain anonymous, said the smell coming from Mr Stewart's flat was "putrid", and made her feel "ill to the stomach".
She was shocked that no other tenants had reported the smell of "off fish" coming from Mr Stewart's home.
"The fact that in 2009 a person died in the flat and wasn't discovered until 2010, in exactly the same flat... I thought tenants were going to report it.
"It's a bit hard to miss that smell, so I wonder how it was missed back in 2010 and now."
She believed Mr Stewart's body had been in the flat for at least two weeks after his death.
"The last time I saw him was last year - he didn't really come out of his flat much from my observation."
She believed the council needed to do more for its vulnerable tenants.
"A person can lie in their flat for six months before it gets discovered. That shouldn't be happening. It is seriously disturbing.
"It makes people feel uneasy that dead people lie in their flats."
A Wellington City Council spokesman said the circumstances surrounding Mr Stewart's death were unfortunate.
"It is unfortunate with his young age, him keeping to himself, and having no next of kin here.
"We are talking about a guy who is in his early 60s ... and if these people want to keep to themselves there is not much that we can do about it. We have to weigh up their privacy."
Mr Stewart's death has been referred to the coroner.
