The MTR Corporation on Monday said it's deeply concerned about two recent incidents involving its trains that severely disrupted services.

In a statement issued after the breakdown of a train on Monday morning on the Tseung Kwan O Line, the rail company announced it will carry out a comprehensive review of its asset management and maintenance regime.

After being briefed on the recent railway service incidents, the MTR Board urged "the MTR management to carry out in-depth investigations and make improvements to ensure a safe and reliable train service."

The chairman of the MTR, Rex Auyeung, said "the corporation has to conduct a review on its existing asset management and maintenance regime to ensure the management of railway assets can be maintained at a high standard."

Hundreds of MTR passengers were forced to abandon a train and walk along the tracks on Monday morning after a fault in the coupling between two carriages brought it to a halt.

It was the second MTR tunnel evacuation in just over three weeks, after dozens of people escaped along the tracks when an accident on November 13 saw two sets of doors ripped off a train at Yau Ma Tei Station.

Lawmaker Gary Zhang, a former MTR engineer, repeated his concerns about the lack of frontline staff at the rail giant, including maintenance workers. He told RTHK the accident might be connected to this.

"I'm worried that this shortage of manpower could be related to the recent major failures," he said.

Zhang also called on the government to take a leading role in the investigation.

"Perhaps the EMSD (Electrical and Mechanical Services Department) should take the lead in the investigation, [and] not just rely on MTR internal investigations," he said.

The government has told the rail corporation to submit a preliminary report on Monday's incident within three days.

The EMSD said the MTR also has to submit a detailed investigation report within two months, accounting for the mishap and its causes, as well as suggesting improvement measures to prevent a recurrence of the problem.

The MTR's chief of operations engineering, Nelson Ng, said there was a fault in the coupling connecting two compartments of the train as it entered the station. A safety device was triggered to stop the train, he added.

Ng said the train did not derail.