Cathay Pacific has apologised to customers after technical issues temporarily disrupted a number of services, including flight bookings and online check-in.
The services affected started returning to normal after 2pm on Thursday.
Various services online and at self check-in kiosks were unavailable "due to a system issue", according to the flagship carrier.
Airport check-in counters were not affected and Cathay's flight operations remained normal.
"We apologise to our customers for the inconvenience caused and are grateful for their patience," the airline said.
It had earlier advised passengers to arrive at the airport at least three hours before departure to allow sufficient time to complete check-in formalities.