Emergency services in Canberra received more than 300 calls for help when a storm swept across the capital on Saturday night.
Up to 65mm of rain fell in some areas as strong winds downed trees and power lines.
The ABC reports some suburbs are still waiting for power to be restored.
Calvary Public Hospital in Canberra also lost power for about 20 minutes when a backup generator failed to start. Water got into the generator, but no surgery was being performed at the time.
Priority calls were dealt with overnight and the remainder were being tackled on Sunday morning.
AAP reports the storm meant that an Australia Day fireworks display was cancelled as a safety precaution.