Firefighters will do backburning on Saturday night after a "good firefighting day".
In an 8pm update, ACT ESA commissioner Georgeina Whelan said there was good news for the community, in that fire activity on the Orroral Valley fire was decreasing.
The ESA planned to do backburning operations on Saturday night to help prepare the fire ground for more work tomorrow.
"You will see some flames out there this evening, that is the constructive backburning we are putting in place to reduce fire activity on the fireground tomorrow, to slow the progression of that fire down towards Tharwa, and to work towards more permanent containment suppression and hopefully extinguish that fire as it works towards Tharwa in the coming days.
"Planning is now in place to lay more retardant suppression lines between Tharwa and Gordon tomorrow.
"Over the next six hours the fire intensity is expected to be moderate. Occurrences of spot fires will decrease, however there is still the potential for those spot fires."
She said firefighters would also get the chance to attack the fire as it emerged from Mount Tennent.
"The fire is currently less than 200m from grassland on north side of Mount Tennent. We are expecting it to reach the grassland this evening and at this time the active suppression activity ... will commence," she said.
"There are multiple containment strategies that exist to the north of Mount Tennent, these include new and improved fire trails. retardant lines - you would have seen the aircraft this afternoon dropping the retardant - ... and we have increased cleared areas between those retardant lines. So we have multiple backdrops to support you and support my firefighters in firefighting activity this evening."
Preparatory work around a communications tower on Mount Clear had been successful.
"This has been a very important win for us today in order to be able to maintain our trunk communications going."
Initial reports were that "fire crews have been able to save all structures in the ACT, including our precious Alpine huts and historic homesteads. I know I might sound very buoyed and I hope you are too because this has been a good firefighting day for us, in terms protecting our cultural assets and critical infrastructure."
Meanwhile, the Clear Range fire spent much of Saturday at emergency warning.
Homes and outbuildings have been lost in the area between Bredbo and Michelago, NSW Rural Fire Service community liaison officer Beth Slender said.
"We know that with the fire behaviour that we've seen and the area that's been impacted, that it is highly likely that we will see some structural losses."
The numbers are as yet unclear.
Just before 5pm, the Orroral Valley fire was downgraded to "watch and act" alert again, after being moved to emergency at 3pm.
Earlier, Ms Whelan said the effort to protect Tharwa, which was two kilometres from the firefront, involved "multiple containment strategies".
"These include new and improved fire trails, retardant lines, and wide, clear areas to allow ground-based firefighter attack. Numerous firefighting resources are also established around Tharwa and south Tuggeranong suburbs."
Authorities were also preparing containment lines between Tharwa and Gordon, which is one of the three southernmost Tuggeranong suburbs.
The Orroral Valley bushfire has burnt the equivalent of about 55,000ha - or about 23 per cent of the ACT's about 236,000 ha.
At 3pm the fire was across the road from the Namadgi Visitors Centre and was spotting into the mulch beds at the centre.
On Saturday morning, ACT Chief Minister Andrew Barr acknowledged it was going to be a stressful day for 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.
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"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.
MORE COVERAGE OF A.C.T. FIRES:
- What you need to know about the state of emergency
- Erindale College evacuation centre open to those who need help
- Colinton residents prepare to defend homes from fire
- ACT temperature soars past 40 but high humidity provides fire relief
- 'We're staying to fight': Brumby brothers prepare for fire to hit
- Horse owners band together after evacuating to EPIC
- Flare-up on Kings Highway, traffic control in place
- 'When it does happen, it's game on': Queanbeyan brigade deployed to Michelago
- Elevated fire conditions to hit the ACT on Saturday afternoon
- ESA to 'lean forward' on evacuations if fires threaten suburbs
- 'Potential to spread close to suburbs of Canberra': ESA reveals predicted fire spread
- How the fire is being fought from the air
- Michelago braced for fire on Saturday
- Authorities issue warning over 'disaster tourists'
