Witnesses said one of the rotors appeared to have hit something as Greg Gribble came down, TVNZ reported. Lance Sheppard, one of those on the scene, said the rotor clipped the pylon Gribble had just put up.
The helicopter broke in half in the crash and parts were scattered some distance away, with some making holes in the windows of an events center several hundred yards from the crash. One person on the ground suffered minor injuries, emergency workers said.
Gribble and his son, Jaz, operate Helisika Helicopters, which has two machines. Jaz Gribble said his father has put in thousands of hours of flying time and has a good safety record.
The crash delayed installation of the Telecom Christmas Tree. Telecom said it hopes the tree will be up by the beginning of December.