A security breach at Melbourne Airport has caused flight delays and cancellations, with the flow on effects expected to be felt at other airports across the country.
Some passengers were even forced to disembark their plane just before takeoff to go through security again.
Melbourne Airport told news.com.au there was an issue with screening passengers at Terminal 1 and all passengers are now needing to be rescreened.
Qantas manages security operations in Terminal 1 and said a passenger appeared to have "inadvertently passed from an 'unscreened' area to a 'screened' area" of the airport.
"As a precaution all Qantas operations have been put on hold and passengers in the terminal are being rescreened, which is causing delays to some services this morning," Qantas said in a statement.