Police were speaking with other members of the group to clarify the circumstances leading up to the tragedy.
Next of kin were yet to be notified.
The death follows a drowning in Waitemata Harbour in Auckland early today.
A search was launched after boaties heard a man shouting out for help in the water near the Chelsea sugar refinery, on Auckland's North Shore, shortly after 1am.
The police Eagle helicopter and police launch Deodar searched for the man around the Chelsea refinery and West Harbour.
The launch crew found his body in the water near the refinery about 2.05am.
Today's drownings come after a Westport man died after he was swept off rocks on the West Coast during a king tide.
David Edward Pascoe, 56, had been fishing at Charleston, about 20km south of Westport, when he was washed into the surf by a freak wave about 5pm yesterday.
Police, surf lifesavers and the Solid Energy rescue helicopter searched for Mr Pascoe.
He was found bout 6.30pm at Nine Mile Beach, about 1km north of where he was washed off the rocks.
Searchers tried to resuscitate Mr Pascoe but he was not able to be revived.