A passport security system outage at Sydney and Melbourne international airports is causing huge delays for passengers trying to fly overseas. International passengers at Sydney and Melbourne are being checked-in manually, leading to a backlog causing flights being delayed for hours. A Melbourne Airport spokeswoman says check-in for international flights was impacted on Monday morning by the outage of the Advanced Passenger Processing system – a globally-used, border-clearance process affecting many other airports.

Additional Australian Border Force officers will be deployed at airports as required to minimise the impact to passengers.

The Department is aware of an external system outage with the Society International Telecommunications Aeronautiques (SITA) system, this will affect travellers entering and departing Australia,’’ a statement on the ABF website says.

As of about 11.00am AEST, it is understood the SITA system was working once more at Sydney Airport.

The glitch affected the passport check that airlines do when a passenger checks in, not passport control itself. During the outage airlines were forced to manually check the validity of passengers passports to ensure they were in order before going through passport control.

As a result there were flight delays out of Sydney Airport of international flights for up to 60 minutes. International arrivals and domestic flight schedules were not affected.

The Australian has contacted SITA seeking clarification on the outage and its cause.

“Thanks for your patience this morning. Most airlines are now checking-in for flights. Delays may take a while to work through the system,” Melbourne Airport tweeted at 10am on Monday.

AAP understands a number of airlines are processing manual check-ins for passengers.

Those flying internationally are advised to contact their airline to check the status of their service.

All international flights to and from Australia are subject to mandatory APP reporting provided by airlines through the APP system, according to the Department of Immigration and Border Protection.

“This facilitates a more streamlined border clearance process for travellers and enhances the Australian Government’s ability to target security concerns,” the department’s website states.

Passenger Chris Walker-Bush tweeted his frustration earlier on Monday. “Nobody able to check-in at Sydney Airport. Nobody. I’ve never seen lines this long in an airport,” he said.

Flight check-ins are also being affected across the Tasman, with Auckland Airport tweeting “Immigration NZ’s national system has gone down. Updates to follow”.

Check-in delays right now as Immigration NZ's national system has gone down. Updates to follow – thanks for your patience this morning.

— Auckland Airport (@AKL_Airport) May 21, 2017

Further afield, there are reports that Dublin Airport is also experiencing delays at passport control.