Jetstar system outage causes flight delays

Jetstar declared its flights are "back on track" after the budget airline was hit by a system failure this morning that caused delayed flights nationwide.

The outage occurred at 8.30am and lasted for about an hour leaving hundreds of frustrated customers queuing in airports throughout Australia.

Screens at the Jetstar check-in counters told passengers of the system failure and apologised for the inconvenience.

The airline has said the fault has been fixed and it is investigating the cause.

"About 8.30am this morning there was a brief outage that lasted for under an hour. This caused some delays to flights earlier today but they were minimal," a Jetstar spokeswoman told nine.com.au.

"We are now getting back on track and everything is looking good."

"We apologise to customers for any disruption caused to their travel plans."

The outage came on the day of warnings about power blackouts in NSW as temperatures in some parts of Australia soar towards 40 degrees.