A woman has been taken to hospital in a serious condition after the boat she was on sank in the Hauraki Gulf in the early hours of Thursday.
Police say the boat hit rocks on the northern side of Motuihe Island at around 4:30am.
A man swam for an hour to reach the shore and raised the alarm.
The man's wife was left clinging to the side of the vessel.
Rescuers found the woman in the water at around 6:50am.
She is being treated in hospital for hypothermia.
Coastguard duty officer Mark Fletcher says the pair were wearing life jackets.