ACT Fire & Rescue is managing a switchboard fail at the Canberra Hospital with ACT Health and ActewAGL.
More than 150 people have been evacuated from building two and five.
Firefighters were called to the incident at 5:40pm. The switchboard is still smouldering and ActewAGL are providing assistance.
There is significant smoke logging in the lower level of the buildings. Smoke doors have been used which have prevented smoke from entering the upper levels.
Units are conducting atmospheric monitoring and will remain on scene for some time.