A countrywide IT glitch left hundreds of Qantas passengers fuming on the tarmac and in airport terminals as planes were grounded.
The tech issue grounded flights for about two hours but disruption lingered.
The airline warned of a knock on effect for the rest of Sunday with a logjam of delayed flights.
The outage impacted flights around the country
It also affected departures from New Zealand.
It comes as pressure mounts on Qantas for weeks of disruption culminating in its worse ever performance in June.
More than 8% of all domestic flights were cancelled, while baggage handling service delivery remains a major issue.
Qantas Domestic and International CEO Andrew David addressed frustrated passengers by issuing an apology.
The airline is also facing possible strike action from baggage handlers.
