According to the ACT government, there are currently 112 people detected with the infection, bringing the total number of cases in this latest outbreak to 2167.

Health Minister Rachel Stephen-Smith said that there were 40 people with the new, highly-infectious Omicron variant.

Three of the current cases were in hospital, though none of them were on ventilation or in intensive care.

In the 24 hours, there were 4025 negative test results.

The rising numbers being tested has been prompted by fears about the Omicron variant and whether - or how - it will spread from the big outbreak in Newcastle.

The indications are that the exponential growth of cases caused by Omicron hasn't happened - or at least been detected - yet, though over the weekend, a flight into Canberra from Newcastle was labelled a close contact exposure site.

There's been pressure on the ACT testing sites, with people told to return the next day in some cases. The problems weren't helped over the weekend when testing had to be stopped at one of the drive-through sites because of the storms.

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.

New pop-up sites have opened. 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.

Vaccination rates are high. The government said that 98.4 per cent of people living in the ACT, aged 12 and over, had been fully vaccinated.

NSW recorded 2501 COVID-19 cases in the 24 hours until 8pm on Sunday - a drop of 65 cases on the previous day's record high of 2566.

However, the number of people in hospital is gradually creeping up and health experts say cases will explode in January without a return to some restrictions.

Further south, overwhelming testing demand has created long queues and forced several sites to shut as Victoria reported 1302 new COVID-19 infections and no deaths.

It is the first day the state has not reported a COVID-related death since September 16, and there are 13,175 active cases in the community.

Strong testing demand in the lead-up to Christmas is putting the state's testing system under pressure, with long lines forming on Monday morning.

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