A four-year-old girl has died in a rugby scrum machine incident at Mountfort Park, near the Manurewa Rugby Club rooms.
Police said the family were present at the time and were now being supported by Victim Support.
They said the incident, which happened around 6.35pm on Thursday, was not being treated as suspicious.
Manurewa-Papakura ward councillor Daniel Newman said he understood children were playing with scrum equipment when the accident took place.
"And a little girl's lost her life - it's one of the most tragic situations, just before Christmas."
The exact chain of events has not yet been established, he said.
The death had shocked the rugby community in Manurewa, and will trigger an outpouring of grief and support for the girl's family, Mr Newman he said.
"I have spoken at length with the leadership at the Manurewa Rugby Football Club and know Mountfort Park well. We are all devastated at what has occurred. Club members are cooperating with the police to assist their inquiry.
"While the specific details are not yet known, every effort will be made to assist the police to establish what caused this accident.
"A touch module is run at Mountfort Park as part of a programme to encourage active sport; I understand the park was being used for that purpose at the time the accident took place.
Mr Newman said as the councillor for the community and as someone who has spent years supporting the roll-out of sport and recreation at Mountfort Park, the incident was devastating.
Mr Newman said the need now was to establish the facts and support a grieving family.
Donnie Rihari, who is a regular user of the fields at the park, said the incident was a shock to the Manurewa community.
"I know we have our label of south Auckland but Mountfort Park... it's a good place for the community. All kids of all ages use this park."
What happened was a "real tragedy," he said.