The ACT has recorded 30 new COVID-19 cases at the five-week mark of its lockdown.
A source could be found for 19 of these, including 15 people who were household contacts of existing infections.
Of the latest cases, at least 14 were in the community for some of their infectious period and 12 in quarantine the whole time.
It's the ACT's equal second-highest number of daily cases since lockdown began five weeks ago.
Mr Barr indicated it was too early to know whether Friday's figure was a one-off.
"But it is clear that this is not a good number," he told reporters.
Chief Health Officer Kerryn Coleman cautioned the figure did not at this point indicate an upwards trend.
However, epidemiologists noted the effective reproduction number - which represents how many people will pass it on to - had crept above one.
In August, 30 new daily cases were recorded while 32 infections were reported in a 24-hour period earlier this month.
Case numbers have generally hovered between the teens and 20s.
Authorities conducting a compliance blitz have shut down some residential construction sites.
Mr Barr labelled the public health breaches "unforgivable" a week after residential construction was allowed to restart.
"It's simply not good enough and the sites have been shut down," he said.
Police checks at major roads in and out of the ACT will ramp up as school holidays begin on Saturday.
"It is a timely reminder that you cannot travel anywhere for a holiday. You cannot leave the ACT unless you have an essential reason," Mr Barr said.
NSW has recorded 1,248 new infections and 12 more deaths, with the pressure on its hospital system expected to spill over into the ACT.
Mr Barr flagged he would raise the issue of hospital capacity with his territory, state and federal leaders at national cabinet.
In the ACT, eight people are in hospital with the virus. One of them is in intensive care requiring ventilation.
Meanwhile, the proportion of the territory's eligible population to be fully vaccinated is sitting at 52.3 per cent.
Slightly more than 76 per cent have received one dose.
About 98 per cent of Canberra's aged care workforce have met the national vaccination deadline for at least one dose.
Of those, 83 per cent are fully vaccinated.
