The scene of the crash on Auckland's waterfront.

The scene of the crash on Auckland's waterfront.

The scene of the crash on Auckland's waterfront.

The scene of the crash on Auckland's waterfront.

The scene of the crash on Auckland's waterfront.

The scene of the crash on Auckland's waterfront.

The scene of the crash on Auckland's waterfront.

The scene of the crash on Auckland's waterfront.

The scene of the crash on Auckland's waterfront.

The scene of the crash on Auckland's waterfront.

The scene of the crash on Auckland's waterfront.

The Civil Aviation Authority (CAA) says it is amazing no one was seriously hurt when a helicopter crashed on Auckland's waterfront this morning.

Did you see the crash? Email us your newstips, photos and video to newstips@stuff.co.nz

TVNZ A helicopter crashed at Wynyard Quarter on Auckland's waterfront while putting up a Christmas tree.

The helicopter was working to put up the city's Telecom Christmas tree, when it appeared to clip a wire and spin out of control.

"It's extraordinary that the people at the accident site actually suffered little or no injury," CAA Safety Inspector Steve Walker said from the scene this afternoon.

SUPPLIED GREG GRIBBLE: Has been involved in a helicopter crash at the Auckland Viaduct.

Greg Gribble, of Auckland firm Helisika Helicopters, was able to walk away from the crash at 10.30am with only minor injuries. He was now recovering at home after being discharged from Auckland City Hospital shortly after midday.

Walker said it was not clear what caused the crash and the CAA would study footage, including a livestream of the accident on TVNZ website, "in depth" as part of their investigation.

Preliminary crash findings are expected to be released in a month.

Once the CAA completed an examination of the crash scene the wreckage would be released to its owner for removal.

Gribble's son Jaz, who spoke to his dad on the way to hospital, said earlier today he had only just landed from another job when he heard about the crash.

"I spoke to him not long after and it sounded like he was okay. But he was obviously quite shaken, as you can imagine."

Jaz said he was "very relieved" to talk to his father, who has been a pilot since the early 1990s.

"I don't think it's quite hit home yet. I've only just landed but my phone's been going crazy. I just want to find out and make sure everyone's okay, that's my main concern."

At that point he had not seen footage of the crash.

Jaz, who was also a pilot, says the accident is probably the "closest call" his father has ever had as a pilot. He said his father had one other incident a "long, long time ago" where water in the helicopter's fuel had caused problems, but he did not believe that was as serious as the accident today.

An Auckland City Hospital spokesman said Gribble had been assessed in the hospital's emergency department before being released at 12.30pm.

The Christmas tree was being put up near the Te Wero Island bridge connecting the Viaduct and Wynyard Quarter on the waterfront.

The dramatic footage shows the helicopter crashing, and other workmen running away from the spinning rotor blades.

It also shows the pilot being helped from the crash scene.

A St John ambulance spokesman confirmed Gribble was taken to Auckland City Hospital with minor to moderate injuries.

Fire communications spokesman Tony McDonald said the pilot was the only person in the aircraft during the accident.

"All it's basically done to him is spun him around like a car crash, so he'll still have his wits about him."

McDonald said they were bombarded with 111 calls as a result of the accident occurring in such a populated area.

Five trucks and two specialist fire crews were at the scene, including one equipped to deal with any fuel leaks though it did not appear the fuel had leaked.

The helicopter appeared to be hovering just above the ground when the accident happened.

Witness Steve Hall said the helicopter appeared to be trying to lift a tower near the drawbridge.

It then hovered below the tip of the tower where the blades clipped the connecting wire, threw the wire into the air and sent the helicopter into a spin before it crashed into the ground, with the cockpit pointing up into the air.

Hall and several others, including Grant Cantlay, were watching from a boat moored in the viaduct and said they remarked that the blades were getting close to the wire before they struck.

They saw one person get out of the crashed helicopter and onto Te Wero Island in the viaduct, near where a number of superyachts are moored.

Jason Aarsen, a security guard for Formworks, also saw the drama unfold.

He said the helicopter was using a cable to erect a ladder. As the helicopter came down the cable went slack and the rear rotor blade clipped it.

"I heard a massive whack, like two power cables connecting and it [the helicopter] fell from the sky.

"It snapped in half, it was pretty intense."

He could not see the blades on the helicopter as it crashed and feared they might fly off and hit people.

"I almost wanted to duck."

Eyewitness Rosalie Thomson had just got out of her car at the viaduct when the chopper went down.

"We heard this almighty crash and the whole ground shook," she said.

"We could smell it too, all the dust and things in the air."

The helicopter remains tangled in a tower.

A witness said the bridge which connects the eastern viaduct with the Wynyard Quarter had been closed for the day.

Fire, ambulance and police were at the scene.

The Telecom Christmas tree is an Auckland institution. Once erected, it is expected to be seven-stories high and more than 100,000 people will visit. It is scheduled to open on December 2.

Telecom confirmed on Twitter the tree belonged to them and that the pilot and ground crew were all okay.

A Telecom spokesman said their intention was to still put the tree up but said there was a "bit of work to be done" before that happen.

He said Telecom will take its cue from official investigations as to whether the launch date will be postponed due to the accident.