A 9-month-old Rotorua baby is in stable condition at Starship Hospital after suffering head injuries.
Child Youth and Family are investigating how the child suffered serious injuries, including head injuries, police say.
A Rotorua Police spokesman said they were called to a Selwyn Heights home after a family member raised the alarm with a neighbour.
Police arrived at the Korimako St house about 6.15pm on Friday, where the baby had been in the care of extended family, he said.
The baby was initially taken to Rotorua Hospital but later transferred to Starship Hospital in Auckland.
No charges have been laid.
An Auckland District Health Board spokesman confirmed the baby was in a stable condition.
- Fairfax Media