Thirteen were endemic to New Zealand and more than 60 per cent were deep-water species.
"In the upper North Island the shark most commonly seen from the shore off popular swimming beaches is the bronze whaler," Mr Duffy said.
The sharks most often seen "cruising" at the surface by people in boats were blue sharks and mako and in northern waters, boaties were also likely to come across hammerheads.
"The size of all three species generally increases the further from shore you get," said Mr Duffy.
"Around most of New Zealand the sharks most often caught by people fishing from boats are spiny dogfishes, carpet sharks and school sharks.
"If you catch a shark and want to release it safely, avoid taking it out of the water if possible and cut the trace off as close to the hook as possible.
"Large sharks can be kept quiet at the boat by motoring it forward so that water continuously flows over their gills," he said.
"Most sharks will begin to suffocate as soon as they stop moving and will struggle to free themselves if restrained beside a stationary boat."
Boaties and swimmers were unlikely to chance upon aggressive sharks, which tended to stay deeper and further from shore.
Spearfishers were "most likely to have aggressive encounters with sharks because sharks are attracted and stimulated to feed by bleeding and struggling fish".
Mr Duffy said spearfishers could avoid attracting sharks by removing catch from the water as soon as it has been shot, or keep it on a long float line.
"If a shark shows up and wants your fish, let it have them, get out of the water and move location."
