Three Bangladeshi workers are believed to be trapped under a 300-tonne concrete span which had dislodged and fell at an Mass Rapid Transit (MRT) worksite.

The span had dislodged while construction of the parapet was being carried out on the guide way, Mass Rapid Transit Corporation (MRT Corp) said in a statement.

MRT Corp confirms that three workers are unaccounted for and are believed to be trapped underneath.

They are Bangladesh nationals Mohamad Faruk Khan, Mohammad Elahi Hossain and Mohammad Alauddin Mollik.

"No members of the public were involved in the incident as there is no access to the site. The location of the incident site is within the former RRI land near the future Kwasa Damansara MRT Station," the statement read.

Rescue efforts are currently on-going and an emergency response team is on standby at the site.

All work along Package V1 where the incident occurred has been suspended until further notice. The work package contractor for Package V1 is Syarikat Muhibbah Perniagaan dan Pembinaan Sdn Bhd.

MRT Corp Chief Executive Officer Datuk Wira Azhar Abdul Hamid, who is at the site, expresses deep regret over the incident.

“Although investigations are underway, MRT Corp assumes full responsibility for the incident. Once investigations are completed, action on those responsible will be taken,” he said.

The incident has occurred at an MRT worksite within the former Rubber Research Institute site near Kota Damansara.

An emergency response team, the police and Fire and Rescue Services have been mobilised and are on standby at the site of the incident. An update will be issued with further details