It was the second water death of the day after a person died at Te Puia Springs in the Waikato town of Kawhia at 1.50pm.
Water Safety NZ chief executive Daniel Gerrard said there had been 18 preventable drownings so far this year, a quarter of last year's total in less than a month.
This time last year, there had been eight.
Gerrard said their data so far had shown "older guys behaving badly" was the area they needed to focus on.
"They're a difficult group to engage with, but it's really about being out there with your mates and not being 'that guy' that does the foolish thing," he said.
"[We need to get] any messaging we can to those guys to stop and think about their family, about their friends, before they jump in, or turn the motor on the boat.
"It's often not seen as risky behaviour – it's overestimating your ability and underestimating the conditions."
He was not expecting any fewer people on the waterways this long weekend, even though New Zealand was now at the red traffic light setting because of the spread of Omicron.
Findings from the 2021 statistics showed 84 per cent of the drowning victims were male, and 96 per cent of the Māori drowning deaths.