Health authorities expect the ACT will then reach the 80 per cent target by mid-October - but have flagged that gradual lifting of the territory's lockdown would not depend entirely on reaching vaccination thresholds.

Chief Minister Andrew Barr has also said the territory government will include people aged 12 and over, rather than just 16 and over, in its vaccination targets.

The ACT government expects Canberra would take about one additional week to reach 70 per cent coverage, when including 12- to 15-year-olds in the targets.

Epidemiologists expect the rate of vaccination in Canberra will accelerate in September with increasing supply of Pfizer doses and high demand for the vaccine.

But as Mr Barr sets a higher goal of 90 per cent coverage for the ACT - a target he hopes it will reach by Christmas - experts also warn vaccination rates could slow after 80 per cent.

Australian National University epidemiologist Darren Gray said after the ACT reached 80 per cent coverage, the remaining population would include people who could not be vaccinated, were hesitant, or were opposed to vaccination.

Professor Gray said health authorities would need to focus health campaigns on people hesitant about Covid vaccines, after reaching the 80 per cent target.

"You need a lot of effort then to get them over the line," he said.

Monash University infectious disease modeller Michael Lydeamore said nations with higher vaccination rates had reached 70 per cent quickly, but had moved from 70 to 80 per cent in nearly the same amount of time.

"The higher you go, the slower it gets," he said of vaccination rollouts in nations such as Israel.

"I'd be surprised to see Australia over the next 12 months get above 95 per cent. I think that will be an exceptionally high coverage to achieve."

The ACT chief minister on Monday expressed confidence the territory could reach 90-95 per cent, with high vaccine take-up and bookings across age groups.

An ACT Health spokesperson said vaccine hesitancy was traditionally low in Canberra, and was unlikely to affect the territory's vaccine rollout in the near future.

"ACT government clinics are essentially booked out for the next two months, with thousands of new appointments being made each day," the spokesperson said.

"Where vaccine hesitancy is identified in community cohorts, ACT government provides appropriate clinical information sources to support informed vaccine decisions including encouraging discussions with individuals' primary care providers."

Nearly 41 per cent of people aged 16 and over in Canberra have received both vaccine doses.

Vaccine take-up is expected to accelerate with the scheduled arrival of 21,000-30,000 doses per week of the Pfizer vaccine throughout September, 15,000-22,000 a week of Astra Zeneca, and the first arrivals of Moderna.

The ACT would reach 70 per cent on October 12 and 80 per cent on October 27, according to figures on the Covidlive website collating national vaccination data for people aged over 16.

Mr Barr last week said the ACT government believed that, at the current rate, the territory would be the first jurisdiction to the reach vaccination targets in the national reopening plan.

He has also said the rollout will not stop there, and is pushing for 90 to 95 per cent - a target he wants Canberra to reach by Christmas.

The Chief Minister told reporters on Monday that vaccination take-up and bookings had been high across age groups, putting the ACT on track for 90-95 per cent coverage.

"The clincher here will be what 12- to 29-year-olds do. They will seal the deal of getting us to 95 per cent," Mr Barr said.

Dr Lydeamore said the target was a high one, and could face challenges if the rollout began to overlap the period when boosters were required for people vaccinated earlier this year.

"If you have to boost everyone in six months' time, and it takes you six months to get to 90 per cent, you've lost the front end and you'd have to vaccinate them again, as well.

"It is a real concern and phase 1a vaccines, for our front line workers, started in February this year. So we're already getting close to having to deal with that."

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ANU epidemiologist Peter Collignon said the ACT should aspire to vaccination coverage of 90 per cent or above - and that it could be more likely to achieve that than other areas.

"We haven't got people spread out in the countryside, large distances away. And we have a highly educated and compliant population," Professor Collignon said.

Epidemiologists said the ACT's geography, and an above-average take-up among 40- to 49-year-olds, were among the driving forces for the territory's faster vaccine rollout to date.

"We're quite a discrete area, and there's no real hard to reach places in the ACT. It's made it easier for people to get vaccinated," Professor Gray said.

Deakin University epidemiologist Catherine Bennett said vaccinations were above-average for the ACT's 40- to 49-year-olds, despite the group becoming eligible for vaccinations later in the rollout.

"In the ACT, they're not your biggest population groups, but at 40-49 you've got this really high level of uptake that stands out across other states, because usually that's where it slims," she said.

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