The ACT warns it doesn't have enough Pfizer vaccines to cover all under-40s as the federal government ramps up its rollout to young Australians.
It comes as the territory's coronavirus caseload sits at 83, with children and young people making up the majority of cases.
Schools, child care centres, nightclubs, bars, the city's light rail and various bus routes are among more than 250 exposure sites.
Health Minister Rachel Stephen-Smith supports the federal government's expansion of Pfizer eligibility to people between the ages of 16 and 39.
"It was good to hear the prime minister yesterday talking about this, but it was also a little frustrating that we didn't get any heads-up that this was happening," she told ABC radio on Friday.
In the ACT, people in their 30s can already make a booking for Pfizer. From next month, GPs will be able to dole it out to all aged 16 and over.
But the ACT's vaccine clinics are booked out until mid-October.
"Until we have more clarity about what the supply from the commonwealth is going to look like into September and October, it's very hard for us to open up new appointments and to extend that eligibility for our ACT government clinics," Ms Stephen-Smith said.
Younger adults can talk to a doctor about getting an AstraZeneca vaccine, supplied across the bulk of the ACT's general practices.
One third of eligible Canberrans are fully immunised and almost 60 per cent have had their first dose.
Children make up 43 per cent of the ACT's first outbreak in 13 months, while 46 per cent of infections are in people aged between 18 and 44.
Pfizer is being provided to children between the ages of 12 and 15 who are Indigenous or with underlying medical conditions and compromised immune systems.
This is expected to change soon, with Australia's expert immunisation panel expected to expand eligibility to all children in that age group.
ACT health officials are calling for nurses or anyone with nursing training to help replace staff caught up in the outbreak.
More than 600 healthcare workers across Canberra Health Services and Calvary Public Hospital at Bruce had been isolated or quarantined.
The government expects case numbers to jump around over the coming days and warns restrictions depended on what happened in NSW.
Chief Minister Andrew Barr says it's impossible to "seal Canberra up in a bubble and have it operate as if there is no Delta variant spreading around Australia".
Despite the outbreak, federal parliament is returning for the last two weeks of August.
Treasurer Josh Frydenberg stresses it's good for the country to see that the "normal course of business continues in the nation's capital".
Many politicians plan to attend remotely to try and ensure the safety of the two-week sitting.
