She said her nephew was a good swimmer and the family had no idea what went wrong. Police say Mr Wanoa got into difficulties when he got caught in a rip.
"He got into some kind of trouble and the boys tried to save him but I'm not sure what happened," she told the Herald.
"It was an accident. No one really knows what happened. Everyone is in shock."
Mrs McGhee said when the group diving with him realised something was wrong, Mr Wanoa's son and grandson dragged him onto the rocks and tried to revive him. But it was too late.
"At least they were with him."
Mr Wanoa's body is being taken to Rotorua for an autopsy and will then go to Gisborne where he will be laid to rest, said Mrs McGhee.
When news of Mr Wanoa's death spread through the whanau, relatives took to Facebook to speak of their loss.
Blanche Wanoa said he died doing what he loved and that she was in shock because he knew Puatai Bay well.
"The big fella musta wanted him more than us [sic]."
Damian Wanoa said Mr Wanoa was one of the best divers he knew and Esther Haerewa said he was a "humble, witty person" with an infectious personality. She offered her condolences to his wife, the Corrections Department's Lower North Island operations director Matire Kupenga-Wanoa, and his children.
Police said his death had been referred to the coroner.
Wanoa was one of eight people to die in water-related accidents since Christmas Day:
•Jimmy Laulu, 3, of Flaxmere, drowned on Christmas at Ocean Beach in Hawke's Bay during an outing with family and friends on Christmas Day. He had been missing for more than an hour before anyone realised he was gone.
•A 33-year-old man and a woman in her 40s, from China, also died on Christmas Day after getting into trouble off Ruapuke Beach, near Raglan.
•Jack Martin, 12, was killed on Boxing Day when he fell of an inflatable sea biscuit and was hit by a passing vessel on Blue Lake in Central Otago.
•An 82-year-old woman was found dead in a pond near Kerikeri in Northland, also on Boxing Day.
•On December 27 the body of Whanganui man Jordan Marshall was found after he was swept to sea at Castlecliff Beach in Whanganui on Christmas Day.
•On December 28, the body of Pawan Kumar Khadka, 22, of Nepal, was found in the surf at Tauranga. He had been living in the city for about 18 months. Police believe he entered the water in the early hours of Monday morning and had likely drowned.
