A diver is recuperating at the Devonport Naval Base after suffering decompression sickness during a dive.
The man - aged in his mid-20s - was diving off Great Mercury Island, off the coast of the Coromandel Peninsula yesterday.
Auckland Westpac Rescue Helicopter crewman Karl Taylor said they winched the man off a boat just after 7pm.
The diver was not alone at the time, and had been diving to depths of 25 to 30 metres.
They treated the patient with high-flow oxygen and fluids to rehydrate him, Mr Taylor said.
The diver was then transported to North Shore Hospital where he was established, before being taken to the hyperbaric chamber at the Devonport Naval Base.
A Waitemata District Health Board spokesman said the diver was "doing well" and was expected to be discharged later today.