Repeat not likely - experts

Over most weekends this summer, people had seen sharks out on the water, including hammerheads, blue sharks, bronze whalers and mako sharks. Photo / Supplied

Great white sharks are no strangers to Muriwai and the warm weather this summer may have brought them closer to shore.

But great white attacks are incredibly rare and a repeat of yesterday at the West Auckland surf beach is unlikely any time soon, experts say.

Marine biologist Craig Thorburn, a curator at Kelly Tarlton's aquarium, said great whites had been common around Muriwai for a long time.

"On the west coast, there's a very consistent prevalence of white sharks that are moving through that area."

Mr Thorburn said the chances of a shark encounter increased during summer, when the water was warm and more people used beaches.

Over most weekends this summer, people had seen sharks out on the water, including hammerheads, blue sharks, bronze whalers and mako sharks.

Mr Thorburn said great whites mainly fed on fish, other sharks, stingrays and sometimes marine mammals such as seals.

Malcolm Francis, principal scientist for the National Institute of Water and Atmospheric Research (Niwa), said great whites gathered at seal colonies and dead whale carcasses, where there was plenty of food.

Muriwai was not a hotspot, but great whites have been known to come right into the shallow water.

"I wouldn't really expect individuals to stay in one place for a long time, but having said that, they could be there for days or even weeks."

Dr Francis said a repeat attack was unlikely. "Given that we have white sharks in our waters most of the time, it indicates that they don't target humans and it's a very rare event to actually attack a human."

New Zealand had a very safe history of shark encounters. About a dozen attacks are reported a year in Australia, and four a year in South Africa.