Any move to significantly reopen the country before 80 per cent of over-16s are vaccinated has been labelled unsafe by ACT Chief Minister Andrew Barr.

Canberra had 12 new COVID-19 cases on Monday, as the territory government weighed up whether to extend the lockdown that is due to end on Thursday.

Mr Barr has also hit back at federal threats to cut support should states and territories continue locking down once Australia reaches vaccination thresholds of between 70 and 80 per cent.

“There’s this glossing over in the debate ‘oh 70 to 80’. Well, let’s stop talking about 70 because it’s not safe at 70,” Mr Barr said on Monday.

“But 80 is the more realistic step. So, 70 will be a gentle step forward, 80 would be a more significant one.”

Mr Barr said a 70 per cent vaccination threshold equated to about 56 per cent of the nation if under-16s were counted.

“That’s why there’s a massive risk at 70 per cent. And no, states and territories won’t be able to come to the rescue of each other,” he said.

Mr Barr hoped the ACT would be at 90 or even 95 per cent vaccination coverage by the time the national double-dose rate for people aged 16 and older reached 80 per cent.

He also warned systems to test, trace and quarantine positive cases would not be optimal if there were thousands of new cases a day.

NSW had 1290 local infections on Monday, while there were another 73 in Victoria.

Mr Barr pushed back on federal Treasurer Josh Frydenberg’s warnings about reduced lockdown support once key vaccination thresholds were achieved.

“The Commonwealth Treasurer can speak for himself and will make all of the sort of muscular assertions around what the Commonwealth will or won’t do and that’s perfectly within his right,” Mr Barr said.

“The lived experience has been somewhat different. The national plan does not prohibit lockdowns beyond 80 per cent.”

The ACT has achieved an over-16 full vaccination rate of slightly more than 40 per cent, compared with about 34 per cent nationally.

Mr Barr flagged a decision could be announced on Tuesday about whether to extend the territory’s lockdown beyond three weeks.

Of Monday’s 12 cases, six were linked and at least half had been in the community while infectious.

“We do not want all of the hard work over the last few weeks to go to waste by opening up too early,” Mr Barr said.

Canberra has 236 active cases, including 12 in hospital and three of these in intensive care.

All but one of the hospital patients are unvaccinated. Another has received a single dose.

Health authorities still haven’t determined the source of about 20 of its total 261 cases since the outbreak began.

-AAP