The MTRC has been asked to submit a report on why smoke was seen emitting from one of its trains, Secretary for the Environment, Transport & Works Dr Sarah Liao says.

About 8.20am today a Tung Chung Line train heading for Hong Kong Island started emitting smoke near Siu Ho Wan on Lantau Island.

Some 600 passengers on board were evacuated after the train arrived at the MTRC's Siu Ho Wan Depot. No-one was hurt in the incident.

Dr Liao said passenger safety is of utmost importance, and the Environment, Transport & Works Bureau's Railway Inspectorate is working with the MTRC to see if routine inspections are sufficient. They will also check the company's inspection procedures and see whether they need upgrading.