Passengers aboard the Singapore Airlines plane hit by deadly turbulence have told of their terror as the Boeing plunged more than 1800 metres in just three minutes.

“I was asleep, and then I was woken up because I was thrown to the roof and then to the floor,” Melbourne woman Teandra Tukhunen told Sky News UK from Bangkok’s Samitivej Srinakarin hospital on Wednesday.

Tukhunen, who was not wearing her seatbelt when the turbulence hit, had her arm in a sling.

“I woke up because of the turbulence, and then when they put on the seatbelt sign, pretty much immediately, straight after that I was flung to the roof, before I even had time to put my seatbelt on unfortunately,” the 30-year-old said.

“It was just so quick, over in just a couple of seconds and then you’re just shocked.”

Tukhunen thanked the pilot, who she said “saved our lives”.

“We’re alive, so that’s all that matters in the end,” she said.

She was among 30 passengers injured when flight SQ321 hit severe turbulence 10 hours into its journey from London to Singapore on Tuesday. A 73-year-old British man, identified as Geoffrey Kitchen, died of a suspected heart attack.

At least eight Australians were in hospital on Wednesday, after the Boeing 777-300ER’s emergency landing in Bangkok. In all, there were 56 Australians onboard, among 211 passengers and 18 crew.

Many passengers were in the middle of eating breakfast when the plane encountered what has been termed “sudden extreme turbulence”.

“Just went to the loo, came back, sat down, bit of turbulence and suddenly the plane plunged,” a 68-year-old British passenger named only as Jerry told the ABC.

He and his wife were among many who hit their heads on the ceiling of the plane.

“Some poor people walking around ended up doing somersaults.

“It was absolutely terrible.”

Aboard flight SQ321 in the aftermath of the turbulence. Photo: X

Allison Barker told the BBC that her son Josh was on the plane.

“I don’t want to scare you, but I’m on a crazy flight,” he texted to her.

“The plane is making an emergency landing… I love you all.

Barker said she endured a “terrifying” two hours before she learned her son was alive.

“It was the longest two hours of my life … it was petrifying,” she said.

Kitchen, a father of two, was travelling with his wife Linda for their “last big holiday” – six weeks in Australia. She is in hospital in Bangkok.

“They were looking forward to the holiday. They are travellers, they do quite a lot of these things, quite adventurous,” his cousin, Stephen Kitchen told Britain’s Independent newspaper.

“It was sort of going to be their last big holiday. It would have been nice to see them before they went.”

On Wednesday, Home Affairs Minister Clare O’Neil said her thoughts were with those affected by the mid-air incident.

“This is a terrible experience that these people have gone through,” she said.

“The Australian government will provide consular assistance wherever we can, wherever it’s needed to those people,” she told Seven’s Sunrise.

“I know the embassy in Bangkok and the High Commission in Singapore are actively trying to contact those Australians at the moment … we will do everything we can to help.”

A Department of Foreign Affairs spokesman said it was making further inquiries to determine if other Australians were affected.

Singapore Airlines’ chief executive Goh Choon Phong said the company had expressed condolences to the family of the passenger who had died.

“We also deeply apologise for the trauma experienced by all passengers and crew members on this flight,” he said.

“We are providing all possible assistance and support to them, along with their families and loved ones, during this difficult time. The wellbeing of our passengers and staff is our utmost priority.”

Australian and International Pilots Association safety and technical director Steve Cornell, who has flown the same type of aircraft involved in the incident, said the level of turbulence experienced was uncommon.

“There are three categories of turbulence: light, medium and severe …. severe turbulence is quite a rare occurrence. You frequently encounter light and moderate turbulence but severe turbulence is very rare,” he said.

“There would be a lot less injuries if passengers did keep their seatbelts fastened at all times, regardless of if the seatbelt sign is off or on.”

-with AAP