LATAM Airlines Group said flight LA800 experienced a "technical problem during the flight which caused a strong movement" on its way from Sydney to Auckland on Monday afternoon.
"Some passengers and cabin crew were affected. They received immediate assistance and were evaluated or treated by medical staff at the airport as needed."
A passenger on board the Chilean airline flight, who gave his name as Jacinto, said there was a "mid-air drop" that affected multiple people.
"People flew through the cabin. People got pretty injured."
A number of passengers were not wearing their seatbelts at the time, he said.
"People were really scared as well."
Jacinto was not hurt but had to stay on the plane for a while once it landed while paramedics assessed all the passengers.
Another passenger, Valentina, told RNZ the plane "just stopped" about 50 minutes out of Auckland.
"People were flying around and everything was super scary.
"Blood was on the ceiling, people [flew] and broke the ceiling of the plane."
Valentina said she was "very scared" to get on a flight again. She received minor injuries during the ordeal, but had been treated and was doing OK, she said.
Another passenger told The New Zealand Herald she felt a "quick little drop" while mid-air.
"The whole plane just froze."
Hato Hone St John said it was notified of the incident at 3.58pm. Five ambulances, two operations managers, one major incident support team vehicle, one command unit and two rapid response vehicles rushed to Auckland International Airport.
"Our ambulance crews assessed and treated approximately 50 patients, with one patient in a serious condition and the remainder in a moderate to minor condition," the ambulance service said in an update tonight.
"So far, 13 patients have been transported to Middlemore Hospital by ambulance."
Auckland Airport said in a statement its emergency service team "responded to a request for medical support" from the LATAM flight, which had taken off from Sydney in Australia.
LATAM Airlines Group said it regretted the "inconvenience and injury" to passengers and confirmed three crew members were taken to hospital.
LATAM is Chile's national airline and flies frequently between Auckland and Santiago.
Its next flight - LA800 to Santiago - has been cancelled. That flight was originally due to leave Auckland Airport at 6.40pm today.
A new flight - LA1130 - had been scheduled for Tuesday, departing Auckland at 8pm for Santiago.
"LATAM is providing affected passengers with food and accommodation services due to the flight cancellation."
It is not yet known what caused the "technical problem".
A Civil Aviation Authority spokesperson said it was aware of the incident.
"The immediate response was handled by Auckland Airport alongside emergency services. The incident has not yet been formally reported to CAA, though we would expect this in the coming days in accordance with CAA rules."
When the report was received, the authority would work with the operator to find out exactly what happened and why, the spokesperson said.
It would also determine "whether any subsequent actions are necessary from a safety perspective".
- RNZ and NZ Herald
