Hong Kong - "Canto-pop" star Ronald Cheng Chung-kei vowed never to drink again after an air-rage incident which saw him fined by an Alaska court, reports said on Sunday.

He was detained by the Federal Bureau of Investigation after allegedly assaulting crew on a Los Angeles-Taiwan flight, forcing the pilot of the Taiwanese carrier Eva Air flight BR005's Boeing 747, with 365 passengers on board, to divert to Anchorage on Friday.

Cheng, 27, was eventually subdued after a flight attendant, a fellow passenger, the cabin crew chief, the co-pilot and even the captain of the plane were assaulted, said the South China Morning Post.

"I will never drink again," Cheng declared after being fined $2 500 (R15 000) by an Anchorage court on Saturday when he pleaded guilty to assault.

He was also ordered to pay unspecified compensation to the airline and his $50 000 bail will be withheld until the carrier decides how much he should pay.

Cheng was placed on one year's unsupervised probation, but it was believed he was free to leave the United States.

Cheng, who suffered a minor injury when hit with a torch to subdue him during the melee, told the court he had taken half a sleeping pill and believed the drug combined with brandy he had drunk caused his behaviour.

The singer was reportedly drunk and annoying fellow passengers in the first-class compartment, smoking and singing to himself, despite repeated warnings that smoking was banned.

When a flight attendant asked Cheng to settle down after a male passenger sitting next to him complained the star had drunk too much and had been putting his hands on his body, Cheng allegedly pulled her to the floor by her hair, starting a struggle with other passengers.

Cheng then allegedly attacked the cabin crew chief, co-pilot and pilot.

After diverting to Anchorage and handing Cheng over to officials there, the plane continued its journey to Taipei.

"Canto-pop" is a widely popular form of entertainment in Hong Kong and elsewhere in Asia, where performers sing in the territory's native Cantonese dialect. - Sapa-AFP