Constable Dean Oswald stripped down to his jocks before getting to the three troubled swimmers at Ohiwa Harbour, where waves were more than one metre high, stuff.co.nz reports.
They had been in the water for about 40 minutes before their rescuer arrived.
Two more men arrived on the scene with lifejackets to help complete the rescue of the children while Oswald swam further out to save the man.
“One of the boys said, ‘My uncle, my uncle,’ and I saw him further out, lying face-up with waves breaking over him. He was conscious but I’d say pretty close to going under,” Oswald told the website.
“It took about 15 minutes to pull him back to shore – every time a wave came I said to him ‘Close your eyes, close your mouth, we’re going under’.”
The man had tried to save the boys when they got caught in a rip.
Image via CC: Benjamin J Melville