Newcastle Airport has been shut down and most flights are cancelled after a section of its roof collapsed.
The roof in the check-in area buckled under a deluge of heavy rain at 1pm on Sunday.
There are no reports of injuries, but travellers flying in or out of Newcastle have been advised to check with their airlines.
Most services have been grounded, but regional airline FlyPelican remains operational with flights expected to depart as scheduled later on Sunday afternoon.
The Newcastle Knights NRL team were among those affected.
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"We were nearly home but our flight had to return to Brisbane due to storm damage at Newcastle Airport," the team tweeted on Sunday afternoon.
