A three-week-old girl who was injured in her Invercargill home remains in a critical condition in an induced coma in Starship Children's Hospital in Auckland.
Police launched a criminal investigation after the newborn was hospitalised with life threatening injuries early on Monday morning.
Emergency services were called to a Princes Street home about 5.30am and the baby was taken to Southland Hospital by ambulance before being transferred to Auckland in the afternoon.
Inspector Olaf Jensen says 15 police staff are working on the investigation, which includes interviews with the baby's parents, who were at the house at the time of the incident.
Police are not seeking anyone else in relation to the baby's injuries.
Officers spent Tuesday carrying out a scene examination at the house.
The family is being supported by Victim Support and friends.