SYDNEY, Australia - At least 37 people were injured on board an Air Canada flight after the plane hit severe turbulence and had to make an emergency landing.

The plane, carrying 284 passengers and crew, was travelling from Vancouver to Sydney but was diverted to Hawaii.

Thirty people were taken to hospital in Honolulu on Thursday. Nine had severe injuries, officials said.

Air Canada said the Boeing 777-200 jet "encountered sudden clear air turbulence... two hours past Hawaii".

Passengers reported the cabin being bloodied and dented from passengers hitting the ceiling of the aircraft.

"We all hit the roof and everything fell down," Jess Smith told local TV station KHON. "People went flying."

Alex Macdonald, from Brisbane, told Canadian broadcaster CBC News that those on board were "extremely shocked".

"I saw the people ahead of me hitting the overhead baggage compartments and then just slamming back into their seats," she said. (FA)