More than 400 people are quarantining in Canberra homes after returning from Victoria.
ACT Chief Minister Andrew Barr said on Monday 473 people were self-isolating after coming back to Canberra from Victoria, which has gone into a snap lockdown.
The state entered a five-day lockdown on Saturday following a cluster of cases in the community, which leaked from a hotel quarantine facility in Melbourne.
There are now 17 cases linked with the cluster, with Victorian authorities revealing one woman tested positive after attending a family gathering with an infected worker from hotel quarantine.
Several Melbourne tram routes, along with the popular Queen Victoria Market, has been added to a growing number of exposure sites.
Health authorities said one new case was recorded in the past reporting period, but the new case was previously announced as being under investigation on Sunday.
Victorian Premier Daniel Andrews has not ruled out extending the five-day lockdown, which is due to end on Wednesday night.
Following the announcement of the lockdown on Friday, ACT health officials said non-ACT residents were not allowed to travel to Canberra if they had been in Victoria.
ACT residents returning home from Victoria were required to fill in a travel declaration and alert health authorities of their travel plans.
There are also 166 passengers in hotel quarantine facilities in Canberra, after they arrived from Chennai in India on a repatriation flight last week.
In the past 24 hours, the ACT recorded no new cases of COVID-19, with 670 tests coming back negative.
There have now been almost 164,000 negative tests recorded in the ACT since the beginning of the pandemic.
