New Zealand is on track for it's deadliest year in the water in almost a quarter of a century - with El Niño a contributing factor.

Water Safety New Zealand is predicting more than 100 drowning deaths in 2026, with 57 having already happened.

That's 18 more drowning deaths than the same time last year.

Water Safety NZ chief executive Glen Scanlon said they were seeing a real trend of men in particular doing things alone, making the risk of drowning so much higher.

A total of 64 percent of the deaths so far this year were people doing water activities alone.

Of the 57 deaths, 54 were men, Scanlon said.

There was also a noticeable trend around gathering kai - with people fishing off rocks or diving and drowning while doing it.

Water Safety NZ chief executive Glen Scanlon.

RNZ / Baz Macdonald

"Your life isn't worth the risk of that extra fish," he told First Up.

The number of deaths so far was equivalent to a death every 3.5 days.

Numbers had been trending down - with rangatahi previously the most at-risk group.

They were now the least at-risk group - with older men taking their place.

Scanlon said those dying from drowning weren't new to New Zealand.

"The 'she'll be right, I know best, I know this place well' attitude is prevalent across particularly male New Zealanders.

Muriwai Beach the day after a Burmese couple drowned while fishing off the rocks.

RNZ / Dan Cook

"Rock fishing and fishing from a boat - it's wearing that life jacket that makes the biggest difference."

In terms of the impacts of El Niño, Scanlon said Water Safety NZ had been seeing the impacts of higher temperatures in Europe recently - causing more people to head to the water when it gets "super hot".

Scanlon said not only that, but El Niño could also bring different winds, swells and surf.

When summer rolls around, he said they wanted people heading to the water to really pay attention to the conditions as they may be different than they are used to.

Swim between flags at beaches if possible, Scanlon said.

RNZ / Cole Eastham-Farrelly

If swimming or diving, Scanlon said not to do it alone.

Swim between flags at beaches if possible.

If diving, have your health checked prior to make sure you are in a good position to do so.

"We want you to go and have a great time with your family and your mates and we want you to get home safe."