Auckland - England Rugby World Cup centre Manu Tuilagi was detained by New Zealand police after jumping off a ferry as it was about to berth on the Auckland waterfront.
The 20-year-old Samoan-born player, who has been fined 3 000 by the Rugby Football Union, jumped off the ferry, which was carrying other team-mates, as it arrived from Waiheke Island and was preparing to dock on Saturday evening.
A police spokeswoman said he was formally warned about the offence of disorderly behaviour, and then released to the England team management.
"I'm really sorry. It was a silly thing to do and I apologise to everybody for any inconvenience caused," said Tuilagi.
Warren Fowler, the general manager of the ferry company, said the antic was dangerous and that there could have been serious consequences.
"It could have been tragic with vessels coming in here and someone jumping off the back of a vessel when it is going to be reversing shortly," Fowler told the New Zealand Herald.
England were knocked out of the World Cup by France in the quarter-finals on Saturday, losing 19-12.
"A member of the England rugby team jumped overboard from a Devonport to Auckland ferry at 6.48pm last evening," said a police statement.
"He was met by police after swimming a short distance to Pier 3 near the ferry terminal.
"He was taken to Auckland Central Police Station where he was formally warned about the offence of disorderly behaviour then released to the company of the England team management."
Tuilagi had already been in hot water at the tournament when he was fined for wearing an illegal gumshield bearing a sponsor's name.
He was fined NZ$10 000 ($7 500) for wearing the wrong mouthguard in England's game against Georgia.
England's campaign in New Zealand was dogged by off-field problems.
Three players were forced to apologise to a female hotel employee for harassment while Mike Tindall -- married to the granddaughter of Britain's Queen Elizabeth II - admitted he'd misled officials about his night with a mystery woman, later said to be an "old friend" by those close to the England centre.
Tindall initially said he was only in one bar with the woman until photo evidence emerged showing them in a second bar where they "behaved like a smooching teenage couple," according to media reports.