The airport operator said the contractor was carrying out the work to address ageing infrastructure when there was a thunderstorm and “lightning activity intensified”.

“In line with safety protocols, work was immediately suspended and the team evacuated the rooftop.

“In their haste to vacate due to the severe weather conditions, the contractor failed to remove plywood used to cover drainage points for safety, leaving one of the roof drainage systems obstructed,” MAHB said in a statement.

It said the blocked drainage prevented water from flowing off the roof as designed and this resulted in large volumes of water accumulating on the rooftop, which subsequently leaked through the terminal ceiling into the departure hall

MAHB said response teams cleared and secured the affected areas in less than two hours, and all systems resumed normal operations thereafter.

It said the roofing work was part of a year-long project that commenced last April to restore and waterproof the main terminal roof, as part of its broader infrastructure renewal programme.

Yesterday, a video posted on X showed water pouring from the roof and spreading across the floor near the luggage check-in area, with passengers avoiding the section.

The leak was the latest in a series of operational issues at KLIA, including aerotrain breakdowns and power outages.