A spokeswoman for the Brisbane Airport Corporation said a second screening point had been set up to help process people who were affected by the evacuation.

But she said there would still be some delays.

“It was a false alarm, which is good,” she said.

“I haven’t got any specific details on how long it will take [to return to normal operations].

“There will be some delays but we’re trying to sort through it as swiftly as possible.”

She said the situation lasted for less than half an hour.

The shutdown was forced when an unknown element triggered the terminal's alarm system a short while ago, a Brisbane Airport Corporation spokeswoman said.

She said airport personnel were working to determine the cause, but the situation was not being treated as sinister.

BAC was simply following procedure by evacuating the terminal, the spokeswoman said.

“Our policy is to evacuate,” she said.

“We are simply taking precautionary measures. We have no idea how long it will take [for operations to return to normal”.

The domestic terminal was not affected.

Passengers on outbound international flights were encouraged to contact their airlines for latest updates and information.