Armed police found the bodies of a 51-year-old man, a boy aged nine and a six-year-old girl in a Dunedin suburb after responding to a callout on Wednesday night.
Police say the three appeared to have suffered gunshot wounds and a shotgun was found at the house.
The children lived at the house with their 49-year-old mother, who was at home at the time of the incident.
It is understood she fled the scene and was not injured.
Police are still determining the relationship between the children’s mother and the dead man.
Police have launched a homicide investigation and were not seeking anyone else in relation to the deaths.