About 680 Canberra homes and businesses were still in the dark on Friday evening.
EVO Energy said it aimed to restore power to all homes by 4 pm on Sunday - but added that this target depended on no more serious storms in the meantime.
"When safe to do so, our crews are continuing to work through the rain, but lightning may be a challenge in the next few hours," a spokesperson said.
But the Bureau of Meteorology warned that storms were likely.
It issued a "severe thunderstorm warning" late on Friday afternoon, though with the worst hit areas including Yass but not Canberra.
Rain was forecast for Saturday, with the possibility of thunder "possibly severe", but easing on Sunday.
"The sheer volume of damage that was done by that really severe storm on Monday is what's taking so long," EVO Energy spokesperson Alison Davis said.
"We're working really closely with the SES and we're really grateful for their hard work and their support with some of the tree clearing and access."
A community hub was set up at Molonglo ACT Rural Fire Service Brigade in Higgins to service the worst-impacted surrounding region.
The hub is open from 11am to 7pm until Sunday, and offers three showers, three washers and dryers for use, as well as charging stations for devices, ice, food waste disposal and ongoing incident information and advice.
ACT Emergency Services Agency advised on Friday afternoon that rising river levels had caused closures at Point Hut Crossing and Naas River Roads.
