A software glitch has seen check-in systems crash at airports including Heathrow and Gatwick in London, Charles de Gaulle in Paris, Washington DC, Zurich and Johannesburg Airport, as well as Melbourne and Sydney, according to UK newspaper The Telegraph.
Melbourne Airport said on Twitter on Thursday night that their passenger processing system "was down earlier".
A Qantas spokesperson confirmed to Fairfax Media that there had been a systems outage, but that flights were still departing from Sydney Airport.
Heathrow Airport confirmed on Twitter that a "small number of airlines are experiencing problems across the world".
It appears systems are working as normal as of Friday morning.