A fisherman dived into the ocean in a desperate bid to save his friend after he was knocked off rocks by a rogue wave, on Saturday but he was unsuccessful.
The man died after being swept into the water while fishing at Cape Saunders, on the Otago Peninsula.
Another man who was fishing with him was flown to hospital after he jumped into the water and tried to support his friend while waiting for emergency services to arrive.
Senior Sergeant Brian Benn, of Dunedin, said police were notified at 4.07pm that someone was in the water, about 50m offshore.
A second person had gone in after him with a life ring to help him, but the man was not breathing.
By 4.30pm, a rescue helicopter was at the scene.
"By that point they were 150m offshore, and drifting out to sea fairly quickly," he said.
The pair were rescued, but one man was dead at the scene.
The other man was flown to Dunedin Hospital, by a second helicopter, with serious injuries. He was discharged from the hospital's emergency department later that night.
A photographer at the scene, who spoke to one of the men with the pair, said they had been out fishing on the rocks after work when the man was swept into the water.
The photographer said the sea was fairly flat at the time, and there was not a lot of wind.
Snr Sgt Benn said there had been similar incidents at Cape Saunders in the past.
"It's not a great place for rock fishing," he said.
"You can get lulled into a false sense of security."
A life ring was installed using a community board grant, following the death of a man fishing from Cape Saunders in 2010.
Te Runanga o Otakou placed a rahui, or temporary closure, from Taiaroa Head to Tow Rock for 24 hours following the incident.