A police spokesman said sympathies were with both of their families at this difficult time.
"The deaths have been referred to the Coroner."
Hunua Falls: Beautiful but dangerous
The falls are found to the southeast of Auckland city but their scenic setting provides a mask over their dark history.
The waterfall is 30 metres high and the pool beneath is almost 20m deep, featuring a steep drop-off where many swimmers have got into difficulty.
In 2016, two teenagers died at the popular swimming spot in separate incidents, prompting calls for Auckland Council to restrict access.
Peter Lemalu, 17, and Lilatoni Vetemotu, 13, both died at the falls within several days of each other.
Their deaths resulted in a plea to close the swimming hole, but that was unsuccessful.
In April 2016, Auckland Council parks manager Mark Bowater told the Herald there were no plans to fence the falls or assign lifeguards.
"It's an incredibly scenic, beautiful spot [but lifeguards] are not being seriously considered, so there's no fundamental change to the site."
He said using lifeguards would send the message that people were encouraged to swim there, when the council recommends people avoid doing so.