The MTR Corporation says outside experts will be asked to take part in a probe into a train incident on Sunday morning which prompted an evacuation that put one passenger in hospital and caused serious service disruption.

Several doors were ripped off a train in the accident at Yau Ma Tei Station, with officials saying they suspect the bogie of the first carriage slightly derailed.

Services on the Tsuen Wan Line in both directions between Lai King and Jordan were suspended at around 9.30am. MTR bosses said they could not give an estimate as to when the line could be fully reopened.

Transport Secretary Lam Sai-hung said the government was highly concerned about the incident.

"I know several hundred passengers were affected, and I send well-wishes to the two passengers who were injured. I have inspected the scene and have been briefed by the MTRC. The government’s ordered the MTR to complete its probe as soon as possible. It’s also ordered it to resume normal services as soon as possible under the safest conditions, and to announce any arrangements clearly to the public,” he said.

Transport Commissioner Rosanna Law said public franchised bus companies had undertaken to enhance services in the meantime.

She added that authorities would keep in touch with the MTR and would make announcements as soon as possible regarding arrangements for Monday morning's peak hours.

The corporation's CEO, Jacob Kam, said a detailed investigation would be carried out with the help of outside experts.

Kam also rejected criticism of the decision to send some of the passengers involved in the incident into the tunnel, rather than letting them get off the train via the platform.

“We have standard detrainment procedures, meaning that passengers could take different routes to evacuate. Our preferred route is of course through the doors onto the platform – that is the fastest and safest. But using the detrainment ramp going down to the track is also a safe egress or safe evacuation process. In this particular case, both of the methods have been deployed," he said.