People in Tharwa have been told it's too late to leave as the Orroral Valley bushfire escalated on Tuesday afternoon.
"The fire may pose a threat to all lives directly in its path. People in these suburbs are in danger and need to seek immediate shelter as the fire approaches," an ACT Emegency Services Agency statement said.
LIVE UPDATES Orroral Valley fire in Namadgi National Park
An evacuation centre has been set up at Erindale College, the Headley Beare Centre in Stirling and Dickson College.
Earlier on Tuesday, residents in Tharwa and surrounds were told to expect a protracted campaign with the Orroral Valley bushfire.
About 100 people gathered at a community meeting in Tharwa Community Hall, held by the ESA on Tuesday morning.
ACT Rural Fire Service chief officer Joe Murphy said the fire was unlikely to be extinguished or contained in the coming days.
"This is going to be a campaign fire, there is a lot of really dry forest out there, we're putting it to you right now we are not going to hold it, we are not going to put it out today or any time soon," he said.
Mr Murphy told the crowd that Saturday was expected to have the highest fire danger.
"In all likelihood our worst day this week will be Saturday," he said.
"We have some pretty ordinary weather this week and coming into Saturday.
"It is going to be hot and dry with moderate winds for the remainder of this week."
There is a total fire ban in the ACT until midnight Friday but Mr Murphy said it was expected to be extended to include Saturday.
The feeling from the crowd was mixed with those who have rural properties in Namadgi National Park expressing the most apprehension.
Residents of Tharwa Village were more relaxed. Tharwa General Store owner Kevin Jeffery saidon Tuesday morning he was not troubled by the threat.
At 6:30pm on Tuesday evening, with Tharwa under threat, he maintained a similar view.
"It's sort of escalated and it sort of hasn't," he said.
"There was a short burst of southerly winds that pointed it in this direction and it's done some spotting.
"It's hard work for a fire to travel north in these hills.
"There is a lot of bare farmland in the way."
Mr Jeffery said most residents had left Tharwa and about 15 had remained. He said some wanted to return but were not able to get through the road blocks.
Elizabeth Pascoe-Pearce owns a property on Smiths Road, which runs from Tharwa to the New South Wales border.
Ms Pascoe-Pearce has been through the 2003 bushfires where she said the fire had come straight to her door.
"We've been through the 2003 bushfires which was a scary situation but you just don't know, as Georgeina Whelan says," she said.
"She said it's unpredictable. We are prepared and I think they are really well prepared."
Ms Pascoe-Pearce said she fell short of feeling completely confident.
"I mean can you, in a fire?" she said.