The mother of a Kiwi bride and a family friend who tried to save her have drowned in Rarotonga, the day before the wedding.

Judith Lorraine Palmer, 62, drowned yesterday while swimming in a lagoon near where she and her husband, Auckland city police chief inspector John Palmer, were staying.

New Zealand police said a close family friend of the couple, Robert Groves, 64, also died while trying to help her.

The families were neighbours from Birkenhead. Their bodies were recovered by locals about an hour after the drownings.

Both couples were in Vaimaanga, Rarotonga, for the Palmers' daughter Vanessa's wedding which was scheduled to happen today. It has since been postponed.

The pair died in an area notorious for drownings and disappearances, the publisher of the Cook Islands News, John Woods says.

The area is currently being hit by southeasters and a 1.9 metre swell, making it even more dangerous.

"It is a turbulent passage in the right conditions," he said.

He believed as many as eight people may have died in the passage in the last decade.

"It is notoriously dangerous, and there are signs there."

With the swell and the tides, a lot of water would have flooded into the lagoon.

"It is a well known dangerous swimming area, and for fishing."

There a no big resorts near the passage, other than the abandoned Sheraton complex.

Woods said Rarotonga would feel the deaths sharply as the couple were on the island for the wedding.

Vanessa Palmer is a high profile triathlete and is the PE teacher at the Tereora College.

"She is a real personality on the island.

"A really great athlete, you see her on the road everyday, and she really shares her knowledge."

Woods said the families were holding a service this afternoon.

Auckland City District Commander, Superintendent Mike Clement, said the double tragedy has hit Chief Inspector Palmer and his wider family hard.

"We are all reeling from the news and can only imagine the magnitude of the devastation John, his family and the Groves family are feeling," Clement said.

"I know personally that the trip to Rarotonga for Vanessa's wedding was to be the highlight of the year for John and Judy and that much planning and anticipation surrounded it.

John and Judy Palmer had been married for 42 years.

Clement said he and Police Commissioner Peter Marshall had spoken with Palmer on several occasions in the past 24 hours to offer support at "this very distressing time".

Commissioner Marshall had also spoken to the Commissioner of the Cook Islands police and and thanked him for the support he was giving to the Chief Inspector and his family, Clement said.

Groves worked at Nuralite Waterproofing systems in Onehunga. His wife, like Judy Palmer, is a registered nurse.

Nuralite said the company learned of his death with sadness.

"Rob was a true gentleman who, over the past 40 years in the waterproofing industry, built a strong reputation based on integrity, practical knowledge and personal service," managing director John Simmons said.

"The fact that he died trying to rescue his neighbour is the ultimate testament to his commitment to helping others."

Simmons said Groves would be sorely missed be everyone at Nuralite along with all those he dealt with.

"Our thoughts are with his wife Denise, and his family and friends, during this distressing time."

- © Fairfax NZ News