Significantly more than 1000 people in the ACT are due to spend Christmas in quarantine after the territory had a record 102 new infections on Friday.
It is the first time the territory has recorded cases in the triple figures and marked a jump from 85 cases on Thursday and 58 the day before.
But despite the rise, the number of people being treated in hospital for the virus fell from three to two on Friday.
There are no patients with COVID-19 requiring intensive care or ventilation.
Despite changes to the way ACT Health will identify close and casual contacts announced on Thursday, more than 1000 people will spend Christmas in quarantine.
This includes more than 330 active cases and close contacts. Health Minister Rachel Stephen-Smith said there were 900 people in quarantine on Thursday and this number was expected to rise with the additional 102 cases and identified contacts.
"My expectation is it will be significantly over 1000," she said.
But Ms Stephen-Smith said the high vaccination rate should give people confidence going into the Christmas period, with 98.5 per cent of people aged 12 and over double dosed.
She also said the ACT government had been preparing for shortened booster intervals but weren't expecting the Commonwealth to announce it on Friday.
Booster intervals will be brought forward to four months after the second dose from January 4, and then down to three months from January 31.
States and territories are able to move ahead of the schedule if they have the capacity.
But this won't be the case in the ACT with the government-run mass vaccination hub closing until January 4.
"Our health system staff are exhausted. We really need to give our staff a break over this Christmas, new year period," Ms Stephen-Smith said.
"We cannot stand up new staff over a break at very, very short notice. That would be completely unreasonable."
But the ACT government is preparing to lift its vaccination capacity in the new year as it continues to scan locations for a second mass vaccination clinic.
"We have a really good track record of once we get the supply of getting the jabs into arms," Ms Stephen-Smith said.
More than 9700 children aged between five and 11 in the ACT have booked in to receive their first jab once the rollout starts for the cohort on January 10.
Australian Associated Press
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