Check-in services at Hong Kong's international airport resumed for hundreds of travellers on Thursday with computer systems restored, after local television footage showed scores of people stuck in queues with their luggage.

The Airport Authority said the check-in system had fully resumed normal operation after a regular test found an "abnormality" in the network's computer system. Registration for check-in at several rows in the city's normally efficient airport were shut during the outage.

"Five departure flights were delayed for around less than 30 minutes during the period," the authority said in a statement.

Cathay Pacific Airways, the city's flagship carrier, was one of the most affected, the South China Morning Post reported. Cathay did not immediately respond to requests for comment.

Hong Kong's airport was one of the busiest international hubs before the COVID-19 pandemic, with more than 71 million passengers in 2019.

The city's government unveiled a promotional campaign dubbed "Hello Hong Kong" beginning in March to lure travellers and business people back to the special Chinese administrative region hit in the past three years by COVID restrictions.

Hong Kong's Tourism Board (HKTB) said this week provisional visitor arrivals tripled in February from the previous month to a three-year high of 1.4 million.

(Reporting by Farah Master, Jessie Pang and Donny Kwok; Editing by Robert Birsel and Sonali Paul)