"Me, my wife, my kids are in and on the water every other day. We are surf lifesavers. This would not be happening if it was three to four nautical miles off Tauranga coast or the Hauraki Gulf."
The only reason cage diving was allowed to happen so close to Stewart Island was because the community's 360-strong population did not have a large enough voice to object, he said.
Mr Mitchell said shark behaviour near Stewart Island had changed and was now a threat to the community. "They had to cancel their school swim days. Kids that used to dive off the wharf at the weekend no longer can. You can't tell me that's just the nature of animals over time. This is directly a result of sharks becoming comfortable being around boats."
People, boats and food had become one and the same to sharks, Mr Mitchell said.
Mr Mitchell said sharks were biting, rubbing and bumping boats and buoys - behaviour believed to have been encouraged by shark diving.
A video capturing the moment a 6m great white shark lunging at a dinghy carrying a film crew near Stewart Island emerged over the weekend, highlighting the call for shark diving to be banned.
Department of Conservation's director of conservation services for the southern South Island, Allan Munn, said it was "highly unlikely" shark diving had anything to do with increased great white activity.
"If we can be satisfied we've got sensible rules around it then why wouldn't we [approve shark diving]?" The permitting system meant cage diving was now safer, and "sharks have been coming into the area since time immemorial".
Shark Experience boss Mike Haines referred inquiries to Shark Dive New Zealand, which said, "we don't have anything further to add to the erroneous concerns raised by the Stewart Islanders".