A pair of scissors in a passenger's carry-on luggage sparked a major re-screening process at Brisbane Airport.
About 2000 passengers are being checked again after airport authorities became aware of the security breach about 8.30am, a spokeswoman for Brisbane Airport Corporation told AAP.
"We are having to re-screen all passengers in the sterile area as a precaution," she said.
"We're not sure why that person wasn't stopped at the screening point. That will be part of an investigation."
She said the airport's multi-layered screening procedures detected the breach.
"We don't like to have to re-screen people but we will always err on the side of caution.
"Unfortunately, scissors are a restricted item."
She said airport staff were doing their best to ensure passengers could board their planes as quickly as possible.