About two dozen people on two flights were injured when their aircraft hit turbulence before landing at Hong Kong's airport on Friday morning.

Thai Airways said 20 people were hurt when an Airbus A380-800 carrying 500 passengers, two pilots and 24 cabin crew from Bangkok encountered "unforeseen turbulence" as it was descending to Hong Kong's airport.

The airline said passengers and cabin crew suffered injuries but the plane landed safely.

Thai Airways sales manager Kenny Kung said earlier that 39 were injured but the airline later revised the number to 20. Kung says the injured were sent to three hospitals in the southern Chinese city.

Local carrier Hong Kong Airlines said three passengers and three flight attendants were hurt when their flight from Phuket hit "sudden turbulence" as it neared the city's airport. The airline said the plane landed safely and the six have left hospital.

The plane was carrying 110 passengers and seven crew.

One passenger described the chaotic scenes inside the plane to local broadcaster TVB.

"Someone was thrown up about one metre high towards the ceiling, and then fell down on the floor," he said.

Hong Kong has been experiencing unsettled weather as Tropical Storm Kong-rey passes nearby.