Passengers on a flight that suddenly dropped while heading to Auckland say they're still in shock and afraid to board a replacement plane after the harrowing experience.
Chilean airline LATAM said flight LA800 had a "technical problem during the flight which caused a strong movement" on its way from Sydney to Auckland.
After landing, passengers told RNZ they were in shock and afraid to board a replacement plane tonight for the next leg to Santiago, Chile.
St John Ambulance says it treated 50 people at the airport and took 12, including a child, to hospital.
The airline says three crew members were among the injured.
Health NZ said injured passengers were all in stable conditions this morning.
Four patients remain in Middlemore Hospital, and one in Auckland City Hospital.
National Director of Hospital and Specialist Services Fionnagh Dougan thanked staff for managing such a large-scale incident.
"This was a significant event and our staff worked incredibly hard with our partner agencies to ensure there was a seamless transfer of patients, and that everyone got the best possible care. We are grateful to all of those involved."
Passenger Brian Jokat said he thought he was going to die in the incident.
"It felt literally like you were at the apex of a rollercoaster, you know that feeling you get when you come over and you're going down.
"That's when I thought this is over and I just swallowed and looked out the window, and just crossed my fingers, and what can you do."
Jokat was wearing his seatbelt and was not injured.
"I never ever strap in, which I will always do now, and I just fell asleep when I first got on the plane and I left it on and the next thing I knew, I was awoken by this massive jolt and the gentleman sitting next to me was on the roof of the plane."
When he first woke up he thought he was dreaming, but there was "mass chaos" throughout the plane.
"Everyone was, they were on the floor, they were on top of each other, bags were everywhere, my shoes were several rows back, no announcements, no abrupt message before, just bang and it was instant."
A few doctors on board helped to treat the injured while some passengers screamed and others were in silent shock, Jokat said.
He said at the end of the flight the pilot came to the back of the plane.
"I asked him, I said 'what happened?' and he said my instrument panel went blank just you know for a second."
A 'technical issue' on board the flight from Sydney to Auckland sent passengers flying through the cabin. Photo: Supplied/Brian Jokat
Passenger Valentina said the plane "just stopped" about 50 minutes out of Auckland.
"People were flying around and everything was super scary," she said.
"Blood was on the ceiling, people [flew] and broke the ceiling of the plane."
The flight was due to continue to Santiago, Chile. A replacement aircraft will now make the trip at 8pm Tuesday.
A passenger who escaped with minor scrapes told RNZ she was scared about getting on the replacement plane.
An Australian woman said she was still in shock.
"It woke me up, I jumped. Drinks went everywhere. And we weren't so bad because we were in business class but the people down the back, because they were closer together, a few people got injured.
"We're ok now, a bit of a shock, it doesn't, well I hope it doesn't happen often."
Others described the ordeal as lasting about four seconds and said there were people with neck and head injuries, and dislocated joints.
LATAM said in a statement an investigation was under way into the "strong shake" on flight LA800.
The carrier apologised for any inconvenience or discomfort.
It said people from New Zealand, Australia, Chile, Brazil, and France were among those taken to hospital.
"LATAM is working in coordination with the respective authorities to support investigations into the incident."
Chile's General Directorate of Civil Aviation (DGAC) announced it would participate in the investigation into the incident.
It said New Zealand would lead the investigation.
DGAC said it had been in contact with LATAM and expressed its regrets for the passengers on flight LA800.
"We reiterate our commitment to the safety of air operations."
St John's District Operations manager Andy Everiss told Morning Report the injuries treated ranged from "bumps and bruises, to more serious traumatic injuries".
14 units, including seven ambulances, were at the airport and staff worked hard to calm patients down, he said.
"There was obviously a lot of emotion on the plane."
Everiss said there would be debriefs about the incident, but he was proud of the response of ambulance staff.
"This one today [Monday] will certainly be one that stands out."
Aviation expert Peter Clark says the flight radar shows the flight was cruising at 41,000 feet and at 15.27pm on Monday it dropped to 40,692ft.
Clark told Morning Report it was not a big drop but something had forced the nose of the plane down.
"So all those people that were not strapped in with their seatbelts became a flying object."
It could have been human error or a software or mechanical fault, he said.
Air New Zealand and Qantas also fly Boeing 787 Dreamliners and a thorough investigation was needed, Clark said.
However he doubted other 787 needed to be grounded.
He said the same thing had happened to a Qantas Airbus flying on Australia's east coast.
It was a timely reminder for people to wear their seatbelts, Clark said.
"When you are in your seat wear your seatbelt, some people are very complacent about this."