Virgin Blue has blamed a power outage at its Sydney data centre for another check-in system outage.
The airline's troubled systems went black for two hours today, again casting doubt over their stability.
However, a spokesman told 7 News that the outage was unconnected to recent IT issues that have affected the airline.
"This morning our check-in and online booking systems were briefly impacted due to a power outage at our data centre. This was quickly rectified," the airline said in a statement on its website.
"Flight schedules are currently in the process of returning to normal. There were some flight delays this morning as a result of the power outage."
Virgin Blue's check in systems went down last week, causing flight delays nationally.
It also suffered IT issues in September and October last year.