ACT Fire & Rescue are on scene at Phillip investigating reports of smoke within the basement of a building along Furzer Street.
Staff have been evacuated from two neighbouring buildings.
The power supply has been interrupted and fire crews are investigating with assistance from fire wardens.
There are four pumpers, bronto skylift hydraulic platform, breathing apparatus van and two commanders on site.
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Update to follow.
More than 2500 people have been evacuated from Scarborough, Sirius and Aviation House.
There is no sign of fire but crews are continuing investigations on all floors of the three buildings.
Power has been restored.
ACT Ambulance Service are also on scene but no injuries reported.
Crews have completed a sweep of all three buildings.
Staff have been allowed to return inside.
No fire was found during investigations by ACT Fire & Rescue.
Firefighters are leaving the scene but have revised evacuation numbers.
It is now estimated up to 6000 people were forced to leave the buildings following a call to Emergency Triple Zero (000) made after a power failure.