Three men, all wearing life jackets, endured rough waters for hours before managing to get to shore safely - only for one of them to succumb to the conditions.
A man was pronounced dead at the scene hours after the boat he and two other men were in overturned at the Manukau Heads, in Auckland, last night.
Emergency services were called to the area just after 9pm after being alerted to the situation by a passerby.
Police say the trio had spent "a number of hours" in the water after their boat capsized.
"Eventually they made it to shore. But sadly, the third man was located deceased on the beach near Manukau Heads," a spokesman said.
"All three were wearing lifejackets at the time."
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The two surviving boaties were taken to Middlemore Hospital to be treated for minor injuries.
Police said they are now working to inform the dead man's next of kin before more information is released.
"The matter will be referred to the Coroner."
A Coastguard spokesman earlier confirmed that its staff were unable to send a rescue vessel to the spot because they would not have been able to access it.
"Once we figured out what the position was, we told the Police we weren't able to get a [rescue boat] there.
"Just based on the initial information we had - which puts it right on South Head. From what I understand, the survivors were under the cliffs."
It was not clear whether the trio had been trying to cross the Manukau Bar - a notorious spot where many other boaties had died over the years.
The incident comes as search and rescue efforts continue for Louis Solofua, 59, who has been named as the man missing from Lake Ellesmere/Te Waihora in Canterbury.
Solofua had been out on a kayak checking fishing nets on Saturday morning when he failed to return. His kayak was found at 2.30pm that day.
Water Safety NZ said yesterday, at 11.30am, that there had been six preventable deaths by drowning so far this year. That figure stood at eight deaths by drowning the same time last year.
The youngest drowning victim to date is 11-year-old Joshua Southon, who died alongside his father, Darren Southon, in a diving accident off the Wairarapa Coast last Friday.
Wellington man Valeliano Mita, 40, died after being pulled out of the water at Seatoun Wharf on Saturday after jumping in to rescue his son.
Mita did not know how to swim but had leapt in to help his son when the youngster fell into the water.