Police at the scene where a body was found in a Housing NZ flat in Titahi Bay, Porirua, on Sunday.

Police and Housing New Zealand each visited the Titahi Bay flat where a man's body lay decomposing for weeks – but left without entering.

The man's wife is understood to have been tending to his body as part of a cultural ritual before it was finally discovered on Sunday.

Wellington police are looking at "certain cultural beliefs and practices" as part of their investigation into the death of the man, who was in his 50s and is believed to have been from India.

Police have confirmed an officer turned up to the house on Friday to investigate a complaint from a neighbour about "an overwhelming smell".

He spoke to the woman who lived there, and looked inside an open window.

"At that time he did not notice anything unusual or detect an overwhelming smell coming from within the house," Detective Senior Sergeant Grant Ferguson said.

"The officer asked her at that time if everything was OK, to which she responded it was."

Housing NZ also confirmed on Tuesday that a contractor visited all properties at the complex last week to test smoke alarms.

The contractor knocked on the door of the dead man's flat and was told by the woman who answered that it was "not a convenient time", communications manager Cassandra Rivers said.

"Our contractor said he did notice a smell when he visited, but at the time he attributed it to rubbish bags that were sitting outside the house."

She said Housing NZ had no issues with the tenancy or the property, which was kept in a clean and tidy condition.

"We are extremely saddened by what has happened and our thoughts are with the family."

Police admitted that, in hindsight, the body could have been found on the first visit.

"Upon further investigation, and based on information known to police, the officer believed that the smell was emanating from a neighbouring property," Ferguson said.

"Based on what we now know, while it's unfortunate that we did not make any further inquiries inside the home of the deceased man at that time, it would not have impacted on the eventual outcome."

Ferguson said he was satisfied the officer made a "legitimate call" based on how the situation presented at the time.

"With the benefit of hindsight, it is apparent that a request to enter the property would have resulted in the earlier discovery of the deceased gentleman.

"However, these were very unique circumstances. This is a very sad situation for all involved."

Neighbours said the couple had family in India, and had lived at the flat, in Te Pene Ave, for about a year.

The wife told neighbours the smell was from cat faeces, and sprayed Dettol outside the flat to cover the smell.

She was taken away by police after the discovery of her husband's body, but has not been charged.

In a statement released on Tuesday, police said initial pathology tests had been inconclusive. They would not say yet whether they would treat the death as a homicide.

Allies Rangihuna, who lived in the adjoining flat, said a neighbour had knocked on the flat's door at least twice, asking about the smell.

He said he first noticed the smell on Thursday, and initially thought it was food that was thrown out to feed seagulls.

Rangihuna said the last time he saw the dead man was about three weeks ago. On Saturday he was having a cup of tea with a mate when he saw the woman walking outside his house.

The woman was spraying along the front of the adjoining flats, "all around the house". "She said 'Dettol, Dettol will get rid of the smell'."

Fellow neighbour Katerina Hill said the couple mostly kept to themselves, but the man used to go out for daily walks. She had not seen him for about four weeks, but had seen the partner right up until last week.

Indian culture and custom expert Pushpa Wood said some Hindu practitioners bathed a person's body and clothed it then kept it in state sometimes for days until a male blood-relative arrived to perform the proper rites. Then the body was traditionally burned on a funeral pyre.

However, the belief that the body was a shell, incubating five elements that were released on death, meant a quick cremation was preferred, as there was a belief evil spirits would occupy the void left by the soul if left too long.

"I think people need to understand what is her belief rather than passing judgment. This could be what she was used to where she has come from and that is all she knows. Or that there are some mental health issues and she does not realise the consequences of keeping a body."

But it was not customary to keep a body in a house for weeks, Wood said.