The victim was taken to hospital by an associate but died shortly after, said Mr Hooper.
The perimeter of Outhwaite park, on the corner of Grafton and Carlton Gore Rds was cordoned off this morning with police or security guards are at each entrance.
Occupants of properties near the park said they did not hear any disturbances last night.
They said people were often sleeping rough in the park and one home owner said people needed to be very security conscious in the area.
• Any information can be reported to Auckland City Police on (09) 302 6400, or anonymously via Crimestoppers on 0800 555 111.