"With these kinds of things the normal practice is for the dog to be seized and there is an investigation. It would be inappropriate for us to make any comment before the outcome of that investigation.
"All I can say in this stage is our thoughts go out to the family involved."
Elsewhere, a 35-year-old Mangakino woman was seriously injured after being attacked by a bull on a farm near the Waikato town.
Emergency services were called to an address at 8.14am.
Barry Vincent, from the Rotorua-based BayTrust Rescue Helicopter, said the woman was hit hard and tossed several metres through the air by the bull.
The victim was in a serious condition, after suffering head injuries, and was taken to Waikato Hospital in Hamilton.
Police did not attend the incident -- the latest to involve a bull recently.
In October, a man in South Canterbury suffered serious injuries after being charged by a bull and in July a man at Tahuna in Waikato was left fighting for his life after being gored.