Passengers booked with Virgin Airlines suffered delays and long queues due to the airline's check-in glitch at airports across Australia.
A malfunctioning internet router had led to the failure of the airline's check-in technology on Tuesday morning.
Virgin, the second largest airline in Australia, issued a statement at 9.30 local time that its check-in issues had been resolved.
However, problems persisted at the Melbourne and Sydney airports even after the airlines declared that the technical issue has been resolved, reported the Sydney morning Herald.
Melbourne and Sydney airports were badly affected due to delay in flights - around 12 domestic flights departing from Sydney airport were significantly delayed while Melbourne had seen the delay of five domestic flights and cancellation of one flight, reported News.com.au.
Due to issues in check-in systems, airline staff were compelled to use manual check-in procedures across the country's airports.
Issues started as the internet router systems of Opus failed.
An Optus spokesman was reported by news.com.au as saying: "An Optus hardware fault affected Virgin Australia's primary ticketing system this morning.
"We understand Virgin Australia manually applied back-up to handle ticket processing.
"Optus apologises to Virgin Australia passengers affected by the temporary outage and are working with our technology vendors regarding this issue."