The Hospital Hill fire burning in the southern remote area of Namadgi National Park has been extinguished.
The fire, which was believed to have been ignited by lighting, had been burning since at least Monday.
"The fire was quickly contained and extinguished in difficult forested terrain thanks to a range of air and ground firefighting tactics," the ACT's emergency services agency said in a statement on Thursday afternoon.
The agency has also declared a total fire ban for Friday and said the fire danger rating was expected to reach severe.
"The Bureau of Meteorology is forecasting hot, very dry conditions with a predicted temperature of 40 degrees," it said in a statement.
It asked Canberrans to review their bushfire survival plan and know what they would do if threatened by a fire.
The ACT's State of Alert continues.