Perth airport was thrown into chaos this morning when it was forced to evacuate departure lounges in terminals 1 and 2 after passengers on a FIFO flight were mistakenly allowed to enter the airport through the wrong door.

The “human error” meant passengers who had already cleared security were required to file out of the departure lounge to repeat the process.

It also left other travellers stuck on the tarmac waiting to be allowed off flights arriving in Perth.

The hold-up occurred because some flights out of remote locations such as mine sites are not subject to the same level of security screening required at Perth Airport.

In this instance, FIFO passengers arriving back in Perth were brought into the departure rather than arrivals area at terminal 2, constituting a security breach that required the entire departure area to be evacuated and every passenger to be re-screened before they could re-enter.

Some of the arriving FIFO passengers walked to terminal 1 before the breach was recognised, requiring the departure lounge at that terminal to undergo the same process.

A Perth Airport spokesman said there was no imminent threat to any traveller and that the evacuations were little more than a security precaution.