Passengers and staff were evacuated from Canberra Airport for about 30 minutes on Tuesday morning as part of a planned safety drill.
A spokeswoman for Canberra Airport said the planned exercise was an annual requirement as part of occupational health and safety standards for the terminal.
The drill allowed testing for warning sirens, signage and procedures, the spokeswoman said.
Passengers were back inside the terminal about a half an hour after the exercise began.
The spokeswoman said it had been planned for a period when the fewest travelers would be disrupted.
Passengers used social media platform Twitter to note the disruption.