The Airport Authority has apologised for a system glitch that left a large number of travellers waiting longer than usual to check in for their flights on Thursday morning.

In a statement, the authority said five outbound flights were delayed for less than half an hour as a result.

The authority said it found out about a defect affecting check-in aisles A to E when it conducted regular testing overnight.

It said it immediately activated its emergency response system and arranged for the airlines affected to use other aisles.

The authority said its registration system was running as normal again by 9:15am.