An air traffic control tower at Canberra Airport was evacuated at 2.45pm on Wednesday after material believed to be asbestos was found in a piece of equipment during routine maintenance.
Air Services Australia have since confirmed testing showed no signs of the material, and air traffic controllers started to return to the building at about 3.45pm.
Alternative air traffic control services were put in place during the period of false alarm to ensure "minimal disruption to services", the company said, while it inspected the suspicious material.
"We ... evacuated the tower to ensure the safety of our air traffic controllers," Air Services Australia's statement said.
Social media users reported the grounding of interstate flights as a result of the evacuation. A spokesman for Qantas said the airline was aware of the issue and was assessing what, if any, impact it had on its flights.
It was understood at least one Qantas flight was called back to the Brisbane Airport terminal as a result.
A spokeswoman for Virgin Australia said none of its flights were impacted by the disruption, including for its other airline Tigerair.