A mother and her young child lived at the home on Moana Ave, neighbour Avia Amosa said.
Mr Amosa said he was woken by screams coming from the adjoining house about 2am a fortnight ago.
He rushed outside to see what was happening and knocked on the door. He said the child's mother answered holding the girl in her arms."She said her girl was very, very sick," he said.
Police were called to the Onehunga home just after 4am today and arrived five minutes later.
"Officers discovered the body of a young child and immediately closed the scene down," Detective Senior Sergeant Glenn Baldwin said.
Police were alerted by the woman at the house, who was later taken away for medical treatment, he said.
An Auckland District Health Board spokesman later confirmed that the woman was now in their care.
Mr Baldwin was not able to comment on the relationship between the two occupants and stressed that the investigation was in its early stages.
Officers were conducting inquiries on the street and immediate area around the property, he said, as well as talking to neighbours. Police are locating and notifying the child's next of kin.
"The priority today is to get well under way with the scene examination, to remove the child's body from the address and to ensure family are notified appropriately," he said.
Mr Amosa said his young children were crying when they heard the news this morning. The youngsters, aged 7 and 8, often play with the young girl who lives next door, he said.
The scene examination is well under way at the two-bedroom house, with a number of investigators entering the house and taking photos.
It is not known where in the house the body of the young child was found.
Neighbour Des Gilmore said he had called the homeowner's parents in Malaysia and broken the news to them. Police have asked Mr Gilmore if he is willing to identify the body, if necessary.
Mr Gilmore said the family moved to the area about two years ago. It is understood the house is a Housing New Zealand property.
He said the mother always looked after the house and her daughter was always clean and nicely dressed. "She was a beautiful girl. That's what hurts me the most. It's very, very odd."
Housing New Zealand and Child, Youth Family say the death is a police matter and have referred all inquiries to them.
- By the New Zealand Herald and NZME News Service
