One person has died every two days in drowning incidents so far this year.
Water Safety New Zealand said that was one more in total than during the same period in 2014.
The latest death was on Saturday, when a 74-year-old man drowned while swimming with his daughter off Peka Peka Beach on the Kapiti Coast.
Water Safety New Zealand chief executive Matt Claridge said more people were swimming at beaches, lakes and rivers because of the hot weather.
"It's up to New Zealanders to ensure that those incidents are minor, they not major, they're not fatalities, and it's up to New Zealanders to take on that personal responsibility message."