Child, Youth and Family (CYF) says it had been searching for a toddler in the weeks before he died in an Auckland house yesterday morning but could not locate him.
Police launched a homicide investigation after James Joseph Ruhe Lawrence, 2, died at an Orakei house.
A post-mortem was carried out today but police but have not released details about how James died.
CYF northern region director Grant Bennett said the toddler came to the organisation's notice four weeks ago.
"We consulted with other agencies, visited the home several times and were actively attempting to find mother and child. Despite this we had been unable to speak with his mother or sight James to check on his wellbeing.''
CYF was working closely with the police in their investigation.
A neighbour of the house where James died, who did not wish to be identified, told APNZ he saw a young couple hurriedly moving into the house at the start of the month.
"She was a youngish woman and he was a tall skinny man. He looked a little bit older than her. He was helping her move the stuff in but he wasn't very co-operative: he was throwing the stuff on the footpath.
"If you're helping your wife or your girlfriend into a house you don't throw all the stuff on the footpath and wait for her to pick it all up and carry it inside, do you?''
He said he did not see any children.
The man's wife said it was common to see police activity in the area,
"It's so common to see police helicopters there that we call it the Friday Flights because they fly over there every Friday ... we were at the bus stop just recently and the police did a raid on a house just adjacent to that one. The area's well known to the police.''