A roller coaster stalled at the top of a loop at China's biggest amusement park, leaving passengers stranded upside down, their legs pointed toward the sky.

Eighteen passengers were left hanging for half an hour several meters above the park on New Year's Eve Monday in the eastern province of Anhui, the China Daily said.

The passengers were riding the "Fireball" attraction at the Wuhu Fangte Amusement Park when the rollercoaster came to an abrupt halt. "Park officials and local authorities rescued the stranded passengers after about 30 minutes and six were rushed to hospital and treated for dizziness," Xinhua news agency said.

Investigations revealed that strong headwind had triggered a mechanical fault, the agency said.