Divers are on the site where historic Auckland ferry the Kestrel sunk at its berth in downtown Auckland early this morning.
"Ferry flotsam visible on the Waitemata from my morning ferry following the sudden sinking of the historic Kestrel at its berth overnight," Auckland Councillor Chris Darby posted on Twitter.
Some divers have been out to look at the wreck in an inflatable boat this afternoon.
Tom Warren, Panuku Development Auckland's general manager of marinas, says the council was told of the sinking just before 6am.
"The harbourmaster rang me this morning, he was advised by his staff that the Kestrel had sunk, unfortunately.
"We're now just working through how to deal with the problem we've got, or the challenge that we have," he says.
Mr Warren says the council will be reviewing CCTV footage to see exactly what time the vessel sunk.
(Briar Marbeck / Newshub.)
The minimal amount of debris has been contained and there is not thought to be any environmental impact.
"The Kestrel was supposedly meant to be completely empty of oil so there should be no problem with that," says Mr Warren. "The bund will hold the flotsam or the debris that's there. Once the Kestrel Preservation Society has contacted their insurance assessors etc, they will start to clean up the debris that's there."
"[It's] definitely a loss for Auckland and for the preservation Society -- they're just coming to terms with it at the moment."
Chris Sattler, chief executive of nearby business Auckland Seaplanes, says the sinking has not affected operations for his company.
"It's a bit of a sad story over the last few years because they were looking to restore the Kestrel and I guess it was just a bit too expensive for the trust to get that off the ground -- they were waiting for something positive to happen and I guess it didn't come off," he says.
Mr Warren says the water where the boat sunk was around 6-7 metres deep.
The Kestrel started transporting people between Devonport and downtown Auckland in 1905.
Newshub. / NZN