A woman thought to be his mother was weeping hysterically.
Meads said it was a traumatic incident to witness.
A St John spokeswoman said the child had been taken to Middlemore Hospital in a critical condition.
A police spokeswoman said WorkSafe would be leading an investigating into what happened.
Detective Gareth Brown at the Harry Beaumont Entrance to the Auckland Botanic Gardens where a 7-year-old boy was crushed by a gate. Photo / Steven McNicholl
Detective Gareth Brown said the boy's family was being supported at Middlemore Hospital.