Passengers on board Singapore Airlines flight SQ321 have described the horrifying moments the plane hit turbulence so violent that more than 30 people were injured and a man died, as a relief flight ferried 143 of the passengers to Singapore.

Eight Australians are among the injured who remain in Bangkok, where the aircraft made an emergency landing on Tuesday night after the flight hit severe turbulence en route from London to Singapore and plunged 6000 feet in about three minutes.