The diver who died at Motiti Island on New Year's Day was 42-year-old Blair Kiddle, a former director of Tauranga law firm Lyon O'Neale Arnold, husband, and father of four.

Blair joined the law firm in March 2007 after serving as a police constable, leaving the police to study law before completing his training as a detective.

Blair Kiddle, 42, died after a diving session on New Year's Day.

A former Tauranga Boys' College student, he was an active sportsman and outdoorsman, and had recently bought the boat he went out diving on with one of his friends.

Blair died on Wednesday, January 1, shortly after returning to the surface after a brief, shallow dive, one kilometre from the south coast of Motiti.

He had only recently learnt to dive within the last few months at a resort in Bali, but Lyon O'Neale Arnold partner Mike O'Neale says Blair was very careful.

'He's a very careful fellow, he even went down and got another tank in case he needed it.”

On Wednesday, Blair had dove to about 15 metres depth for about 10 minutes. He re-surfaced after his first open water dive, and was talking with friends when he appeared to lose consciousness and slipped beneath the water.

His two companions retrieved him from the sea floor and returned him to the boat to start CPR. While doing so they dropped his dive gear, which was later recovered by the Police National Dive Squad.

Tauranga based Trustpower TECT rescue helicopter was also called to the scene. An intensive care St John paramedic was lowered onto the boat using the Port of Tauranga rescue winch, but was unable to revive Blair.

From talking to Blair's companions on the day, Mike believes the death has medical causes, and says gear failure is not thought to be a cause.

Blair is survived by his wife Rebecca, three boys and a daughter.