Watch: Moment pilot plucked from water after crashing seaplane into Auckland harbour

New footage shows the moment rescuers came to the aid of a pilot who crashed his seaplane into the Auckland Harbour.

Ferry passenger Murray was on the water when suddenly a plane nose-dived into the sea.

Murray ran out to the back of the ferry and began filming. He told the Herald the plane started to stand up on its end when he pulled his phone out.

"No one was in the water when I pulled my phone out. The pilot must have still been inside.

"The plane was sticking out standing up on end. Then it slowly went over on its back as we got closer.

"We would have been one of the first three boats there and everyone was yelling. No one was doing anything until a little boat came along and a man jumped off and into the tide to swim towards the plane.

Ferries were quickly on the scene following the crash. Photo / Supplied

"Another person soon popped out above the water which must have been the pilot."

Footage shows a rescuer swimming towards the wreckage in an attempt to aid the pilot.

The pilot made it out safely in what paramedics described as a "moderate condition". The aircraft involved belongs to Auckland Seaplanes, based at the Sealink Base North Wharf in Freemans Bay.

A statement from Auckland Seaplanes said one of their planes - a de Havilland Beaver float plane - flipped near their base in the Waitemata Harbour.

"The pilot, the only person on board, was extracted safely.

"The aircraft is now in the process of being recovered."

The company was working with the CAA to discover why the crash happened - in the meantime flying operations were on hold.

The company thanked local boat and ferry operators who provided assistance.

A fisherman who witnessed the crash said the plane was taking off when it nose-dived very quickly.

The plane nearly somersaulted into the water, the fisherman told the Herald.

A witness on board a passenger ferry nearby described harrowing scenes when the plane hit the water.

"It was flying and all we could see was it kind of coming towards the surface of the water. And then when it hit, it nose-dived and it was upside down. Wheels up in the water.''

Despite the crash-landing, the aircraft remained intact.

A plane has crashed at Auckland's Wynyard Quarter. Photo / Gus Clelland

The witness said immediately after the crash, their ferry turned back towards the site to help.

"It was quite far away [from us when it crashed]. We turned back around...We didn't know what was going on in the back. But we got really close to help out.''

Police metro Auckland shift commander Kai Shao told media that the pilot of the light aircraft was rescued by police boat and was being assessed by ambulance now on shore.

"As far as we know there is no fuel leaking into the harbour," Shao said.

Graphic / NZ Herald

Auckland Seaplanes offers a selection of charter and corporate flights, and offers trips to any coastal destination in the North Island.

Routes on offer included scenic flights around Rangitoto Island and over the Auckland Harbour, and flights over to Kawau Island.

Two planes were used for these flights - DHC-2 Beavers built in 1961 and 1965.

According to the company website, the planes had been "well cared for" with each having one previous owner for more than 20 years prior to purchase.