Baby in critical condition in Auckland hospital

An ambulance was called to the boy's Papakura home south of Auckland on Saturday.

The baby was initially taken by ambulance to Middlemore Hospital after paramedics were called, but was later tranferred to Starship Hospital in the central city.

Police say the boy's parents, aged 18 and 19, as well as his maternal grandmother have provided initial statements and are co-operating with the investigation.

The parents are said to be at their child's hospital bedside.

A specialist child abuse investigation team and scientists from Environmenal Science and Research are at their home.

Child Youth and Family has become involved and is working in relation to an 18-month old who also lives at the address, but it says the family was not previously known to it.

A Starship Hospital spokesperson says the boy's condition remains critical.