Devastated friends of the couple killed in yesterday's horror helicopter crash at Kaikōura have gathered at their family home.

Pilot Andrew Hamish Davidson, 60, and wife Lin Chen, 39, died when their new helicopter crashed at a stony beach 30km north of Kaikōura at about 12.40pm yesterday while on a family trip.

Two of their children were injured, along with a third child.

"This was an incredible tragedy and police is working to support the family and friends of the deceased," police said.

"The family of the deceased have asked for privacy at this time," police said.

Locals who witnessed the machine plunge from the sky rushed to drag wounded people from the wreckage.

The parents died at the scene.

Andrew Hamish Davidson was killed with his wife Lin in a helicopter crash yesterday. Photo / supplied

Transport Accident Investigation Commission has launched an investigation.

Davidson had just taken ownership of the Eurocopter EC120B machine in October.

The businessman from Ohoka in North Canterbury had set up helicopter charter company Glenloch Helicopters Ltd a month earlier.

Friends of the couple gathered at their Ohoka lifestyle block, just north of Christchurch, this morning, where they also operated a B&B.

It's understood that Lin's elderly parents are at the property – but speak little English.

The large lifestyle block features an aircraft hanger and windsocks.

Upset friends have been shaken by the double tragedy and today say they are waiting for information.

TAIC investigators are now out on the beach amid the wreckage. They will give an update on the incident at 1pm.

At 2pm a ceremony and blessing will be held at the scene - organised by local Ngai Tahu leaders based in Kaikoura.

The scene of the crash north of Kaikōura. Photo / Canterbury West Coast Air Rescue

Investigators will comb through the wreckage as they work to understand the circumstances that led to the crash.

It's understood one of the couple's children attends private Christchurch boys school, Medbury.

"Medbury community is deeply saddened to learn of the helicopter crash north of Kaikōura reported earlier," headmaster Ian Macpherson said.

"The school has not been officially contacted by police regarding this tragedy. However, we are actively monitoring information as it comes to hand."

Given that the investigation is in its early stages, Macpherson said it was not appropriate to comment further at this stage.

"Our thoughts are with the family at this time," he added.

"We would like to acknowledge the first responders, together with members of the emergency services for their brave work at the scene of the accident."

Harald Hendel, TAIC's chief investigator of accidents, said there may be people who saw what happened, given the location of the accident adjacent to a busy café on State Highway 1.

He appealed for witnesses – "especially anyone who may have captured the accident on their vehicle's dashcam or other recording devices - to please contact TAIC as soon as possible".

They have set up a perimeter around the wreckage prohibiting public access, in order to protect evidence.

"Their initial work will include inspecting the wreckage, mapping the site, and talking with witnesses. Further evidence gathering in coming weeks and months will likely include examining the helicopter's components, seeking any recorded data from the helicopter's electronics, and obtaining maintenance records."

Fire and Emergency New Zealand (Fenz) operational insurance team member Darryl Papesch was one of the first responders on the scene and said locals had pulled everyone out of the wreck by the time he arrived.

He confirmed the three survivors were children, who were flown to Wellington Hospital for treatment.

"We were having conversations with them, not a proper conversation but they knew their names and how old they were," Papesch said.

"The locals were outstanding, in a chaotic situation they were outstanding.

"All three agencies, Fenz, police, St John, all worked together and just got on with it."

Ian Mehrtens spent his 69th birthday pulling dead and wounded people from the wreckage of the crash across the road from his Kekerengu home- and there's one image that will stay with him forever.

"The wee dolly ... the little girl that was hurt, her doll was in the surf and I just picked it up," Mehrtens said.

"I carried the wee girl up the beach to where her mum was lying. She was asking me 'where's my mummy ... is my mummy all right?' and I said 'yeah she's all right', but she was far from it."

Mehrtens and other locals rushed to the scene and began hauling the victims out, terrified the smoking wreckage would go up in flames at any moment.

He said the pilot was obviously dead and an adult woman was "not looking good".

Three children were injured and pulled to safety, including a boy, and a teenage girl with broken legs.

Mehrtens and his wife Lyn own a lodge opposite the beach where the crash happened - in front of the Kekerengu Store and camp, 30km north of Kaikoura.

They were standing in the kitchen with a friend watching the helicopter land when suddenly, something went terribly wrong.

"It was just coming in to land and I thought he was putting on a display for the passengers, showing them how the helicopter worked," Mehrtens said.

"It started spinning ... then it just disappeared ... clunk ... bang. I thought, 'S**t, oh my God' - it just nosedived down and I thought, 'Crikey, they are going to need some help."

He jumped on his quad bike and headed to the beach, meeting his neighbour and mate - who asked not to be named in this story - on his tractor.

The helicopter had gone down in the water so the men - helped by locals, campers and tourists - tied a rope to the tail and dragged it from the surf on to the beach.

Then they started frantically pulling people out.

They retrieved the pilot last, laying him on the beach and covering his face with a blanket - placing rocks around it so the coastal wind did not blow it away.

"I didn't want to see that," Mehrtens said.

"The poor bugger ... something must have gone really wrong."

He said the helicopter crumpled "like tissue" and his wife described it as being "like tinfoil".

"It just all of a sudden altered course ... there was a big crack and I thought maybe it landed on its runners and they were buggered, but no," Mehrtens recalled.

"[The kids] were screaming in pain ... The older girl, she wasn't good.

"There were six of us trying to get them out - the worst part was trying to get them out of their seatbelts."