Some Canberra businesses deliberately flouted restrictions on the weekend, packing venues with too many people and serving alcohol to standing patrons.
Health Minister Rachel Stephen-Smith said it was disappointing and warned restrictions could be tightened if everyone did not do their bit.
Despite the non-compliance, the government is still yet to issue any fines to individuals or businesses for not following restrictions.
The ACT loosened restrictions on Friday, allowing up to 100 patrons in each room within a venue.
However businesses must still abide by the one person per four square metre rule.
Inspectors attended more than 100 businesses at the weekend - mostly hospitality venues and gyms.
They discovered some venues had too many people, while some were allowing punters to drink while standing.
There was also unsafe queuing observed, and some businesses still did not have a COVID safe plan.
Ms Stephen-Smith said while some non-compliance stemmed from misunderstanding the rules, others appeared to deliberately not follow them.
"This is disappointing," Ms Stephen-Smith said.
"The situation that we've seen in Victoria at the weekend ... is a reminder to us that there is a risk we will have to go backwards and tighten restrictions if we don't all play out part in managing to reduce the risk of spread of COVID-19."
A number of warnings are expected to be issued from the inspections.
"Unfortunately over the weekend on several occasions Access Canberra and ACT Policing did have to ask businesses to reduce their patron numbers," Ms Stephen-Smith said.
"I understand that some follow-up action as appropriate will be taken with some businesses
"Our message to businesses is clear - while we still are taking an educated and engaged approach and our preference is not to issue fines, enforcement action will be taken if that is what is required to ensure compliance with our restrictions."
Chief Health Officer Kerryn Coleman said while the ACT did not have any current coronavirus cases, the risk was still real, especially as travel between states increased.
"The situation can change at any moment," she said.
She said the ACT was tracking to proceed to stage three restrictions as planned, but community transmission would need to remain low.
Dr Coleman sad she would also be considering community attitudes towards social distancing and business compliance.