UPDATE: Hundreds of people were evacuated from Perth International Airport this afternoon.
It is understood the call to evacuate was made after a fire alarm was set off.
The West Australian understands it was a false alarm and people have been allowed to re-enter the building.
The incident occurred just after 3pm.
Flights are not expected to be delayed.
Firefighters from Belmont Fire and Rescue Service were on their way to the scene but were stood down.
People took to social media to post photos and announce the evacuation.
Jason Hutchens tweeted: "Some passengers from the flight my wife was on were evacuated outside without their luggage; assume my wife is still inside."
Some travellers said they were stranded inside the aircraft waiting for other passengers.
"Allowed back in to Perth Airport but nobody can tell us how to get back through customs to the carousel to collect the bags left behind," Tony Williams posted on Twitter.
About 20 minutes later, travellers continued to express their frustration.
"So many angry people at Perth airport trying to get their bags back after evacuation but nobody knows where they are," Mr Williams tweeted at 4.10pm.