An unidentifiable object in a bag, believed to be a weapon, caused a security scare and evacuation at one of Sydney airport's domestic terminals on January 28.

The Australian Federal Police and airport security recalled hundreds of domestic passengers with their luggage when security reviewing luggage X-rays saw the object.

Jetstar and Virgin Blue passengers waited for nearly two hours before they were allowed to re-board their waiting flights.

Paul Timms and his wife, Wendy, returning home to Brisbane, made light of the situation and bought six pizzas to fed themselves and fellow travellers.

"We were told there was a security risk and to stay calm. An announcement told us we had to go through security checks again," Mr Timms said.

"It could have been much worse and the delays weren't too bad. But we were hungry and you never know how long these things will take so I ducked out and grabbed some pizzas."

A Sydney airport spokesman said a breach of security had been discovered and Terminal 2 had been cleared so passengers could be screened again.

"An individual passenger breached security at around 6.40pm AEST," the spokesman said.

"It meant he could have had a potential suspicious item in carry-on luggage. Attempts to locate him failed so we recalled all passengers."