"Our trained crew responded immediately in accordance with standard operating procedures and police were in attendance," she said.
"Intentional jumping off a vessel is always prohibited and our crew are trained to respond accordingly."
Police confirmed they were called to Quay St in Auckland about 3.45pm with a report of a ferry passenger having gone into the harbour.
"The man was quickly recovered from the water. He was intoxicated and subsequently trespassed from the ferry terminal," a police statement said.
A person on board the ferry told the Herald the man was part of a "drunken group" of passengers.
Staff had herded passengers back inside following the incident.
"Earlier another member of this drunk group got over the back rail of the ferry and [swung] from a rope. He was reprimanded by the staff but the group continued behaving in an unsafe way," the passenger said.
Police met the ferry at the Auckland terminal.
A Coastguard spokeswoman said a Coastguard Auckland vessel had been sent to the scene but the person was already back on board when they arrived.