Hong Kong's Mass Transit Railway (MTR) rail operator may face a fine of up to HK$3 million (S$542,000) after a breakdown on Monday (April 10) evening that affected 10,000 commuters, the chairman of the Legislative Council's transport panel reportedly said.

Train services at eight stations along the Kwun Tong Line were down for two and a half hours from 6pm due to a power fault, Hong Kong's Apple Daily reported on Tuesday.

Eight people fainted and were taken to hospital during the breakdown, which trapped an estimated 2,000 commuters for nearly an hour, Apple Daily said.

Videos and pictures circulating on social media show hundreds of commuters in human jams at various train stations, or squeezed together in darkened train cabins.

At one particular station, passengers were made to walk on the tracks to evacuate, the South China Morning Post (SCMP) reported on Tuesday.

Lawmaker Michael Tien Puk Sun said on Tuesday (April 11) morning that MTR could face a fine of up to HK$3 million for Monday's disruption in east Kowloon, SCMP reported. He called for the operator to modify its service recovery measures.

Hong Kong's MTR said on its Facebook page on Monday that services were affected by "a power supply problem near Kowloon Bay Station".

More than 90 bridging bus services were provided, ferrying some 5,000 commuters.

The fault was rectified at 8.25pm, but disgruntled commuters lashed out at the train operator, with many complaining about the lack of direction from staff and unclear announcements.

Hong Kong's MTR had at least two major breakdowns last year - one in October when a damaged overhead cable near Sunny Bay station crippled Airport Express Line services for nearly five hours, and another in December when a signalling system issue delayed services on the Kwun Tong line for two hours during the morning peak period.