A third of ACT businesses inspected on Tuesday were found to be operating in breach of public health restrictions.
ACT police also expect there to be more anti-lockdown and anti-vaccination protests in Canberra over the coming weeks.
Chief Minister Andrew Barr said the overwhelming issue identified after about 100 business compliance checks on Tuesday was staff not wearing or incorrectly wearing masks.
"Wearing a mask is critical. It reduces the risk of you spreading the virus. What we're seeing in our daily numbers is a small number of people who have been working while they're infectious," Mr Barr said.
"If you're not wearing a mask properly, it increases the risk of you transmitting the virus to a work colleague."
Mr Barr said police, Access Canberra and WorkSafe ACT would continue to monitor business compliance with public health directions over the next two weeks.
"[Mask wearing is] absolutely essential to keeping your businesses operating safely and protecting the community," Mr Barr said.
Chief police officer Deputy Commissioner Neil Gaughan said officers in the ACT had done more than 3000 home, hotel and business compliance checks since the ACT went into lockdown last month.
ACT police have also performed more than 11,000 traffic stops since the start of the lockdown.
Deputy Commissioner Gaughan said 26 infringements had been issued since August 12, mainly in relation to people failing to wear face masks and non-essential travel.
The chief police officer said three people had been arrested for breaching public health directions in relation to two anti-lockdown protests in Canberra on Tuesday, and officers expected more protests in the coming weeks but were well placed to respond.
"Over the next couple of weeks, the wearing of face masks will be the primary focus of ACT Policing and our partners," Deputy Commissioner Gaughan said.
The ACT reported 23 new cases of COVID-19 on Wednesday, including 14 linked. At least 11 of the cases had been in the community for some time in their infectious period.
More to come.
