A group of people on a day out on the water near Waiheke had to rescued after their vessel started to take on water.
There were fears it was starting to sink, a Coastguard spokeswoman said, and the alarm was raised about 6pm yesterday.
The Coastguard's Lion Foundation Rescue boat, which was heading to another incident at the time, was re-directed to the more serious situation and rescued 13 people on board.
A spokeswoman said it is understood the group had been on a dive charter boat at the time.