The ACT has recorded another 12 coronavirus cases.
Of the new locally acquired cases, half are linked to known infections or clusters and at least six had been in the community while infected.
Canberra's COVID-19 outbreak is sitting at 236 active cases, with 12 people in hospital including three in intensive care.
Chief Minister Andrew Barr says his government is weighing up whether to extend the city's three-week lockdown scheduled to end on Thursday.
"The Delta strain is very, very challenging to contain and, as today's data confirms, we still have people who are infectious in the community," he told reporters on Monday.
"We still have cases that don't have a clear epidemiological link. This is concerning.
"We do not want all of the hard work over the last few weeks to go to waste by opening up too early."
Pfizer bookings will open for residents aged between 16 and 29 in the coming days.
