Lawmaker and former railway engineer Gary Zhang on Thursday called on officials to look into an incident where a girl apparently fell down the gap between a platform and an automated train at the airport.

A video circulating online appears to show passengers rescuing the girl after her fall.

Zhang, who chairs Legco's subcommittee on railway matters, said the incident could have been fatal.

“First of all, because the system being used at the airport, the Automated People Mover train system, is powered by power supply equipment located near the track, so if she indeed falls onto the tracks, she could likely get electrocuted. That's a very serious risk,” he told RTHK.

“If she falls onto the track, because it's an automatic system, the train might just close the door and move on and there is a high risk of this girl being hit by the moving train.”

Zhang said such incidents are not rare and the Airport Authority should launch a thorough investigation.

"According to media reports, this case doesn't even have a formal incident report in the Airport Authority's own records. I think that's unacceptable," he said.

"The improvement measures are there, but if we don't report the instance and we don't look into the instance properly we will not be able to know that we need to conduct such improvement."

RTHK has reached out to the Airport Authority for a response.