Jetstar abruptly cancels flights out of Sydney Airport

Jetstar has cancelled at least five flights out of Sydney Airport this morning, with customers forced to wait in long queues to have their travel issues resolved.

A spokesman for the airline said the flights were cancelled due to weather, crew sickness and airport curfews.

They are not predicting any further issues and affected customers will be moved on to other flights.

One frustrated customer told 9NEWS he was given no warning his flight to Melbourne had been cancelled.

"There was no text message, just a message on the board when I got here," the customer said. "They still haven't told me why."

He said his 8.25am flight was cancelled and told the next available with Jetstar was at 5pm.

"There are just a lot of people milling about with no idea what's going on," the customer said.

"The lines are Virgin and Tiger were massive because everyone was pushed there."