ACT Emergency Services commissioner Georgeina Whelan says she will "lean forward on warnings" and would rather apologise for being too cautious than not cautious enough as high temperatures and strong winds threaten to spread ember attacks from the Orroral Valley bushfire into Canberra's southern suburbs.
The fire has burnt about 15 per cent of the ACT as of 11am, and is "rapidly escalating" as it moves toward the south-east. Another front is also moving slowly north towards Tuggeranong.
ACT Chief Minister Andrew Barr acknowledged it would be a stressful day for Canberra residents, particularly in southern Tuggeranong.
"We really, really appreciate the support of residents who responded positively to all of our doorknocking activity and information sharing," Mr Barr said.
"We've been aware of this risk for some time and a huge amount of work has gone into protecting lives and property.
"What we don't need is people travelling south towards the fire and I can't stress this enough. You are not needed, you are getting on the way, stay out of the area."
Doorknocking is also beginning to take place in Canberra's western suburbs, in case the fire breaches containment lines on its northern flank.
"We are doorknocking... just to remind our community how they can protect themselves and how to develop their bushfire survival plans and also for us to check in on those vulnerable members of our community," Ms Whelan said.
"I will lean forward on warnings, I will lean forward on evacuations, I would rather apologise tomorrow or Monday for evacuating people.
"I don't want to put people's lives at risk, so I am not being a panic merchant by any stretch of the imagination, but I will lean forward if necessary because I want to protect the lives of every resident of the ACT."
People living in Tharwa, Banks, Gordon and Conder are advised to leave this morning if they feel unsafe, Ms Whelan said.
Mr Barr said he wanted people to focus on cutting down unnecessary energy consumption to avoid putting stress on the power grid.
"People need power for air-conditioning and fans so we are asking people to avoid non-essential power use. Turn your pool pump off. If you don't need to do the washing or put the dishwasher on today, don't do it," he said.