KUALA LUMPUR - Hundreds of AirAsia passengers were temporarily held up by a glitch in its check-in system at Kuala Lumpur International Airport 2 (Klia2) in Sepang, according to Malaysian media reports.

According to the New Straits Times, the system was finally restored after about two hours of down time, although other reports said the glitch lasted just 30 minutes.

A spokesman for AirAsia at Klia2 said the fault was due to an Immigration system failure, said NST.

However, this assertion was dispelled by Immigration Department director-general Datuk Mustafa Ibrahim, it said, who told the NST its system had been operating normally since morning.

"Until now there has been no system failure reported on our part. It is the airline's system.

"This afternoon there were many passengers at the departure hall but our counters were empty," he said.

It was learnt that the alleged system failure took place at about 10am and lasted up to 12 noon, said NST.

A source told the NST that passengers would be placed on the next flight based on availability. Otherwise, their ticket would be replaced with a ticket for the flight on the following day.

AirAsia on its Facebook page said congestion was expected at all major airports and guests were advised to arrive at least three hours prior to departure during the year-end holiday travel period.

This is to avoid the anticipated congestion at most major airports, especially at Klia2, which expects at least 40,000 passengers daily throughout this holiday period.

"Travelling formalities such as customs clearance, immigration clearance and security checks might take longer than usual during this peak travel period," the statement read.