The baby was found on Monday afternoon at a house in Barron Drive, Green Bay.
The New Zealand Herald reported today that the boy, born four to 10 weeks early, was discovered at the home of two Indian women -- a mother and daughter -- who had moved into the house a few weeks ago.
Waitemata police spokesman Kevin Loughlin said the post mortem examination was completed yesterday, but police would not reveal the cause of death while the investigation continued.
Mr Loughlin said police were not seeking anybody else other than those already assisting police with their inquiries.
The house, opposite a playground and near a primary school, has been cordoned off by police.
Neighbour Donna Muru was told by police they were investigating the suspicious death of a baby.
"They asked us if we'd seen anything suspicious, did we see any behaviour that made us think something weird was going on," she told the Herald.
Ms Muru said she had seen nothing suspicious.
Detective Sergeant Sean Hyland-Mills of Waitakere CIB said police had examined the scene and spoken to medical professionals and the child's relatives.
