Child Youth and Family says the South Auckland family of a baby who died after suffering severe head injuries was known to its workers.
The 12-month-old boy died in Starship Hospital on Sunday afternoon.
A St John Ambulance spokesperson says paramedics took the boy to hospital on Friday after he went into cardiac arrest.
Child Youth and Family spokesperson Grant Bennett says although the boy's family was known to the service there was no current involvement.
Mr Bennett says the family's other children are in the care of extended family and the service will work with the wider family to ensure their ongoing safety.
He says Child Youth and Family is also working closely with police, who have carried out a scene examination at an Otahuhu house.
Mr Bennett says the death of the baby is tragic and devastating for all those who loved him.
Police have said they are keeping an open mind and have not categorised the inquiry as a homicide investigation.