A COMPUTER software problem that caused major delays this morning at Sydney, Melbourne and Brisbane airports has been fixed.

The problem with the global system, which allows airlines to check passports, led to long check-in queues for passengers, with some waiting up to an hour.

It’s believed the system went down about 7.30am (AEDT) before being restored about 11am.

Melbourne Airport tweeted that the Advance Passenger Processing system was now back online and all airlines were able to process check-in.

A Department of Immigration and Border Protection spokesman said it was aware of an external system outage with the Society International Telecommunications Aeronautiques (SITA) system, impacting travellers entering and departing Australia.

SITA confirmed the software problem was not due to a cyber attack and was caused by a major telecom failure of a top provider in the datacenter in the UK.

“In response, we implemented an alternative communications link and resumed services. Our teams continues to monitor the situation,” a spokesman said.

“We regret any impact this incident has had on our customers and passengers. Our priority remains, as always, to ensure a stable system so that our customers can conduct their business efficiently and effectively. We are currently conducting a full investigation to discover the root cause and though the service is currently restored, our team remains on high alert.”

Some airlines were able to check-in passengers manually but the issue caused delays.

Passenger Jonathan Harley told news.com.au he waited in a queue at Sydney Airport for about one hour with no movement. Luckily his flight was only delayed about 30 minutes.

“I don’t know about other airlines but Qantas staff on ground were really good,” he said.

“Generally, passengers were patient and understanding.”

A Sydney Airport spokeswoman said passengers should check with airlines for the latest information on their travel plans.

A spokeswoman for Brisbane Airport said passengers were facing longer check-in times but flights were leaving on time.

The Melbourne spokeswoman said check-in for international flights had been affected by an outage of the Advanced Passenger Processing (APP) system.

“This system is used globally, so the issue affects many other airports as well as Melbourne,” she said.

Picture of the mayhem @SydneyAirport this morn. Passport control system down. pic.twitter.com/iJUx1YVkX6 — Jonathan Harley 🚴 (@jharleyaus) May 21, 2017

Nobody able to check-in at Sydney Airport. Nobody. I've never seen lines this long in an airport. — Aussie on the Road (@aussieontheroad) May 21, 2017

“Melbourne Airport is asking anyone flying internationally today to please contact your airline for an update on individual flights, or visit melbourneairport.com.au for the current status of the system outage.”

Meanwhile, one lucky couple managed to get married at Brisbane Airport early this morning and to depart for their honeymoon before the processing delays hit.

This has got to be the most loved-up way to start a Monday at an airport EVER. Congrats Steven & Kellie 💖 #LoveIsInTheAir✈️ pic.twitter.com/O7qZhfjeVz — Brisbane Airport ✈️ (@BrisbaneAirport) May 21, 2017

Brisbane Airport tweeted a photo of the couple known only as Steven and Kellie.

A spokeswoman confirmed to news.com.au that they had wed about 8am (local time) and even held a small reception before departing for their honeymoon.

“We were pleased to help facilitate, and our terminal is beautiful overlooking the tarmac — especially with the fog this morning,” the spokeswoman said.

Luckily the couple had checked in beforehand, and celebrated the occasion with a small group of family and friends before jumping on a plane headed to Bali.