An Invercargill man who witnessed a great white shark bite his rubber raft says cage diving is to blame for them becoming more aggressive and being seen more around Stewart Island.
Roy Barnsdale said the young children who'd been fishing on his eight-metre boat close to shore at Ackers Point near Oban last month screamed when the 3.5-metre-long shark circled the boat then bit the raft, puncturing it.
No one was on the raft, which was tied out the back of the boat, but he quickly motored the children back to shore, he said.
"We could hear the hissing of the rubber raft going down ... so we thought we better start heading to shore."
Roy Barnsdale, who has holidayed on the island for 60 years, said great white sightings were now much more frequent, in large part due to cage diving affecting the sharks' habits.
"The Ackers Point one, there's been a lot of sightings there and a lot of sightings at Dead Man Beach," he said.
"I've just come back from Stewart Island today and there's a rubber raft at Horseshoe Point not far away, two young guys fishing. And I sort of thought, well, how safe are they?"
Mr Barnsdale would not go diving or snorkelling now in spots he used to, he said.
"There's definitely the pattern in sharks' behaviour, there's no doubt about it, it's changed."
He and others put that down to shark cage dive operators trying to attract the great whites, which they argue then associate boats with food.
Some island locals are campaigning to close down cage diving.
The Department of Conservation (DOC) issued temporary permits to the two shark-diving operators in late December, to run through the diving season until August 2017.
From the middle of this month, operators, who have a code of practice they should follow, must install video cameras on their vessels and give the footage to the DOC if it asks.
The High Court is still considering whether DOC has the authority to issue permits and if it does, consider public safety when issuing them.
One operator, Shark Experience, was offering a trip on Monday morning for $469.
Shark Dive New Zealand charges $630 for a dive.
Mr Barnsdale said not only were recreational fishers like him being endangered, but pāua divers' livelihoods were being jeopardised.
"Does it have to take someone gonna get eaten?"