Two Navy divers who reached into the sea to grab a wetsuit hood they thought they had dropped were shocked to find their friend, missing diver Robert Hewitt.

"Kia ora," he said to Lyle Cairns and Buzz Tomoana as they hauled him from the sea yesterday off Mana Island where he had spent the last 75 hours.

Mr Hewitt was last night recovering in Wellington Hospital after his ordeal, which rescuers have called a miracle of endurance and inner strength.

In a statement issued from his hospital bed, he credited the love of his fiancee and family for "getting him through".

"The knowledge that I have gained from the Navy allowed me to adapt to the different conditions."

He also thanked Tangaroa, Maori god of the sea for "bringing me home". Mr Hewitt - formerly a member of the dive squad that found him - disappeared during a dive charter on Sunday afternoon after becoming separated from his dive partner.

A massive air, sea and land search began in the area.

By yesterday the air search had been called off and the family, including former All Black Norm Hewitt, had begun praying for his body to be returned from the sea.

Yesterday it was - alive and well, complete with a grin and a lot of gentle banter.

Mr Hewitt told rescuers he survived by eating the raw kina and crayfish in his catch bag.

He was lucid, although dehydrated and suffering from hypothermia.

After being lifted on to an inflatable rescue boat, he phoned his fiancee, Rangi, to tell her he had survived.

Last night she and Mr Hewitt's three children, Meripia, 14, Casey, 13, and Kiriana, 6, were with him at the hospital.

Senior Sergeant Bruce Adams, who heads the Wellington-based police national dive team, said that when Mr Hewitt was found he was remarkably lucid given his ordeal.

"He's talked nonstop since we picked him up."

When asked what his first words to rescuers were, brother Norm chipped in with: "He would have said, 'I'm hungry, bro'."

Norm Hewitt had been steeling himself for a phone call saying the body of his older brother had been found.

Instead, as he and the whanau waited at Takapuwahia marae, he received the remarkable news that his brother was alive.

"We always knew, bro, we always knew you were coming home to us," he said on Close Up last night.

Weather in the search area had deteriorated yesterday afternoon and any last hopes of finding the 38-year-old had all but faded when police and Navy divers spotted the wetsuit hood about 400m off Mana Island.

Mr Hewitt had been without water for 75 hours and paramedics gave him small sips to slowly begin rehydrating him.

He was kept horizontal because of circulation problems after so long floating in the water, which was a relatively warm 18C or 19C.

The naval officer in charge of the search team, Lieutenant Commander David Turner, said Mr Hewitt's survival was a miracle.

"To spend three days in the open water, that's a lot of courage and commitment. I've been involved in a number of search and rescues and unfortunately they always turn into search and recovery.

"It appeared he had spent the whole time keeping himself afloat ... with only his dive suit and catchbag, having discarded his diving equipment.

"He kept himself alive by eating the kit from his catch bag. He'd been fishing and had caught a couple of crayfish and kina, and he'd cracked those open and eaten them raw to keep himself going for the three nights at sea.

"He had travelled some distance in and out for some considerable time with the movements of the tide."

Lieutenant Commander Turner said the two men who found him were personal friends of Mr Hewitt's and had acted on a hunch.

"The weather was looking pretty marginal for diving today, and so they decided to follow up some local information about a sheltered cove around the corner, where seaweed and flotsam usually washed up.

"They went to see if there was anything there that could give searchers a clue, and it was there they found him."

Warrant Officer Brian Kino said Mr Hewitt's Navy training, personal mana and inner strength had brought him through. Norm Hewitt, at times so emotional he could not speak, described the moment he was told that Robert had survived as "surreal".

"I don't know if there are many words to describe the emotions ... When we got the news, as you can imagine, it was overwhelming."

- additional reporting: NZPA