The number of great white shark sightings near Waihi Beach and Bowentown has "gone through the roof" this summer and local fishermen are being warned there could be more to come.
Such sightings include great whites jumping out of the water and knocking a small fishing boat while local fisherman Dave Hope was inside.
Hope has lived in the area for 20 years and goes fishing once a week. He's only seen a great white there once - eight weeks ago.
He was fishing in the harbour, somewhere he didn't usually go - when a great white breached the water and grazed the boat as he was reeling in a trevally.
"It's a 12-foot tinny, only a small boat ... the shark came straight from underneath," he said.
"I didn't see fins coming towards me, it was just boom, out of nowhere, a big splash and rocked our boat."
He said the shark was about 2.5m and missed the hooked fish.
"If it was six inches over it would've landed on the side of the boat with a bit of weight," he said.
"I couldn't get the motor started fast enough."
Hope said he was so nervous about the shark returning he snapped his line and was now reluctant to fish in the harbour again.
Around the same time, keen fisherman Pete Rogers saw a great white for the first time in his more than 30 years living in the area.
Rogers was anchored on the bar, about 200 metres from land, when what appeared to be a 9kg barbecue gas cylinder went past them "at speed".
"I said to my dad that I reckoned there was a shark tied onto it.
"In the next five seconds, right by the boat, the great white breached straight out the water."
The "huge" shark was about 3m long and close enough for Rogers to touch with his rod.
A week later another, smaller great white breached the water.
"We've always had sharks like the little bronzies [bronze whalers]," he said, but not these aggressive ones.
Earlier this month, Bowentown Boating and Sport Fishing Club commodore Stu Curd said the number of great white sightings had "gone through the roof" since mid-November.
"Five years ago, if someone said there was a great white around you would've been pretty sceptical."
He's lived in the area for most of his life and said the numbers alone were "very concerning".
"In the past, it's just been [bronze whalers] and we've known it but they're relatively harmless. Great whites are a different breed."
While he said he knew the animals did not go out of their way to bite people, they were "a lot more aggressive".
"In all honesty, I would not take my kids biscuiting down the harbour this summer.
"They appear to be more in the harbour, but I'm no expert."
A friend of his was in Cave Bay - between Anzac Bay and Waihi Beach - and his burley pot that had been in just over 0.5m of water was taken out by a great white, he said.
Curd said the water was deep just behind where his friend saw the shark.
Curd organised for leading shark expert Dr Riley Elliot to speak with locals about great whites in the area during a question-and-answer-style meeting in December.
The venue was fully booked, 97 people watched the live stream and 2600 people have since watched the video.
Dr Elliott identified the species responsible for 19-year-old Kaelah Marlow's death as a suspected juvenile great white between 2.5m and 3m long.
He has also identified 15 individual great whites largely in the Bowentown end of Tauranga Harbour.
Dr Elliott said there were unprecedented numbers of sightings and encounters last summer and this summer was likely to be no different.
Elliott said there was potential for the number of sightings to increase, particularly just offshore from Anzac Bay and in the waterskiing lane off Matakana Island.
Elliott said sharks were predatory animals but most encounters did not result in bites, injury and death.
Great white sharks - Department of Conservation:
Females reach about 7m total length and males 5.5 m. There have been reports of large sharks between 9m and 11m.
Little is known of white shark breeding in New Zealand.
Great whites are protected under the Wildlife Act 1953, which makes it illegal to hunt, kill or harm them within New Zealand's Territorial Sea and Exclusive Economic Zone.
Any offence under this Act is liable to a fine of up to $250,000 and two years' imprisonment.
Great whites are protected from fishing by New Zealand vessels on the high seas under the Fisheries Act 1996.