Water Safety NZ is pleading with would-be drowning rescuers to call for help and use flotation devices.
It comes after the second fatal incident in a week involving parents attempting to help their own children.
Jonty Mills, Water Safety NZ Chief Executive, told 1 NEWS it's important to assess the situation.
"I acknowledge that it's natural human instinct to be able to help someone, should they get into trouble - particularly if it's a child," he said.
"But it's really important to understand the risks and know your own limits. Sadly, in most situations, it's the rescuer who ends up drowning. Whereas those who are in trouble survive.
"Call for help in anyway shape or form immediately before entering the water. And before entering the water, try to take some flotation device, whatever that might be," he added.
Last week Wairongoa 'Magoo' Renata drowned at a Far North beach after attempting to save his children, who were dragged out to sea.
Geofrey Rainey was among the first rescuers. Even with years of surfing experience, he was "exhausted" swimming out to help.
"I told [the girl] to grab around my neck. But we both sunk, I realised this is really bad. I don't know how I'm going to keep us both afloat."
Luckily one of the children had a boogie board in the water.
"Had there not been some kind of flotation device, I don't know if we could have saved her at all really.
"I didn't think at all about the necessity of anything to help aid the rescue. I thought 'I can swim, I'll be fine.' And that's probably what a lot of people do. Having gone through it now, obviously I realise and I won't forget it. I don't know how people will remember in that moment of desperation," Mr Rainey said.