Police are investigating the death of a 5-month-old baby girl in Hamilton.

Shortly before 5pm on Thursday, police were called by ambulance staff who had been waved down at a Hamilton East house.

Police said the infant was taken to Waikato Hospital in a critical condition but died about 11am yesterday.

A team of forensics specialists and a police photographer spent yesterday afternoon inside the single-story house on the corner of Peachgrove Rd and Insoll Ave.

Neighbours confirmed to the Waikato Times that ambulance crews were seen outside the house about 4.45pm on Thursday.

The neighbours did not know who lived at the house, but said they would often see an older boy jumping on a backyard trampoline.

“While we first and foremost are supporting the family through a traumatic situation, we need to thoroughly investigate the circumstances surrounding what has occurred,” Detective Senior Sergeant Mark Greene said.

“The investigation is very much in its early stages. We are undertaking a scene examination and a number of interviews as we seek to understand what has happened,” added Mr Greene.

A post-mortem will be conducted in Auckland on Saturday.

- © Fairfax NZ News