Swarms of up to 40 sharks have been sighted off the Coromandel coast over the holiday period as people swim only metres away, oblivious to the danger.
Helicopter pilot Steve Broadbent said he has seen sharks disturbingly close to swimmers on the sandbar between Matarangi Beach and Whangapoua Beach over the past two weeks.
"The heavy [shark] activity began just before Christmas. Some days we've seen up to 30 sharks but on the day the photo was taken [Sunday] we saw about 40," Mr Broadbent said.
"They're seasonal. I saw them two years ago in the same spot, but none last year at all. They're back in force this summer.
"We have seen quite a variety ... bronze whalers, hammerheads and I think makos. There were at least three species."
The sharks were spread across a 300m stretch of Matarangi Beach.
"They were disturbingly close to swimmers, maybe about 20m away from them."
The sharks were swimming in water shallow enough for people to stand in.
"We went and warned people the sharks were close. They got out of the water quickly."
He had even seen two large sharks at Whangapoua Beach in knee-deep water.
Mr Broadbent told the Herald he was amazed no one had been attacked.
"It's amazing there haven't been any incidents with so many sightings ... there's a danger because we don't know what they'll do."
There have been a number of shark sightings in the past three weeks, including one which latched on to the inflatable boat of two lifeguards at Omaha on Monday, partially deflating it.