Long wait times at the two-day-old testing site were recorded throughout the day with some reporting they were turned away early on in the morning.

The Mitchell site was closed more than five hours early on Sunday due to wet weather, with people told to head to the Garran site instead.

"We apologise for any inconvenience this may cause, however the safety of staff and our community is paramount," ACT Health wrote in a social media update.

Sunday's figures bring the total of active cases in Canberra to 103. There have been 2154 cases recorded in this outbreak.

Three people are in hospital, and none are in intensive care.

There were 1721 negative test results received on Saturday.

The jump in cases within the nation's capital mirrors rising numbers seen in neighbouring NSW.

The arrival of the new Omicron variant has put authorities on alert with concerns family reunions and holiday plans could be derailed by the spike in cases.

Long queues for testing sites peaked at the Mitchell drive-through testing clinic where people waited more than two hours.

ACT Health said the Garran walk-in clinic had a wait time of around one hour while the Kambah drive-through site was more than 45 minutes.

Authorities recommended people use the Dickson College pop-up clinic on Sunday to avoid long wait times.

The EPIC drive-through testing site, which was first opened in March 2020, was closed on Saturday and replaced by a new site in Tooth Street, Mitchell. The Tooth Street site is smaller than EPIC.

To curb the demand, the Dickson College pop-up site was opened for this weekend.

In a joint press conference with the federal Health Minister Greg Hunt on Sunday morning, deputy chief medical officer Dr Sonya Bennett urged Australians to continue wearing masks inside even if it was no longer mandated.

"I'd probably encourage everyone to think about continuing to wear masks, particularly in settings that are indoor, public indoor spaces that may not be well-ventilated," she said on Sunday morning.

"Think about wearing a mask. It's a simple, easy thing to do.

"We know at Christmas time the shops do get very crowded. I was there myself yesterday. It was really pleasing to see, you know, a large proportion of people still wearing masks. But probably not large enough.

"I didn't have [my mask], but it reminded me that in the future I will certainly be taking a mask to anywhere that's crowded, particularly around Christmas time, because it's an effective, another effective layer of protection."

NSW reported another record-breaking number of daily cases on Sunday with 2566 cases but no virus-related deaths.

The latest figures are an increase of 84 cases on Saturday's total, the number of people in intensive care remained relatively stable at 28. There are now 227 virus patients in NSW hospitals.

The state's case tally on Sunday marks the highest number of daily infections reported by any Australian state or territory since the pandemic began, beating the record it on the previous day.

Meanwhile, in Victoria there were 1240 new COVID-19 infections and another four deaths.

There are 384 patients in hospital, 84 of whom are actively infected with the virus in intensive care and 43 on ventilators.

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