England rugby international Manu Tuilagi was detained by Auckland police after jumping from a ferry as it was about to berth.
Tuilagi, 20, swam to a nearby pier at the Auckland Ferry Terminal where he was met by police at 6.48am BST and taken to Auckland Central Police station.
The Leicester centre was given a pre-charge warning for disorderly behaviour before being released back to the England team management, who were said to have been "a little bit embarrassed".
Noreen Hegarty, a spokeswoman for the Auckland police, would not confirm the identity of the player but it is understood it to be Tuilagi.
He was detained for around an hour by the Auckland police before he was formally processed. The police confirmed that is the end of the matter.
Ms Hegarty said: "A member of the England rugby team at 6.48pm yesterday (New Zealand time) jumped overboard from a ferry just before it was about to berth at the ferry terminal in Auckland and he swam to a nearby pier. He was then detained by police and given a pre-charge warning for disorderly behaviour and he was collected by his team management."
England's failed Rugby World Cup campaign has been dogged by controversy.
Tuilagi was fined 10,000 New Zealand dollars (£4,800) by World Cup officials for breaking the tournament's strict commercial regulations by wearing a branded gum-shield.
England were found to have illegally changed the balls during their win against Romania and banned coaches Dave Alred and Paul Stridgeon for the Scotland game.
The off-field conduct of some England squad members has been in the spotlight since a group of players enjoyed a night out drinking in Queenstown, and manager Martin Johnson confirmed during the tournament that he had reprimanded James Haskell, Dylan Hartley and Chris Ashton after a female member of staff in their Dunedin hotel was reportedly taunted with lewd comments.