Emerging COVID-19 cases across Sydney have prompted the ACT to continue current travel restrictions until at least January 6.
The rules prevent people from Greater Sydney, the Central Coast and the Wollongong areas from travelling to the ACT.
Any returning ACT residents who visited those areas will need to notify authorities and enter quarantine for 14 days.
Chief Minister Andrew Barr said the ACT would continue to take a risk-based approach to the ongoing situation in Sydney to ensure local restrictions could remain unchanged.
"We have around 1500 people in quarantine at the moment and there have been literally thousands of people pulled over by ACT police as they come back into the territory," Mr Barr said on Wednesday.
"We will continue this level of monitoring, advice and activity."
Chief Health Officer Kerryn Coleman said while the number of new coronavirus cases linked to Sydney's northern beaches cluster had fallen over Christmas, new exposure locations and community transmission had emerged.
She said that continued to pose a risk to the ACT community.
"There are currently around 160 public locations that COVID-19 cases have visited while infectious in NSW, with more than half of these occurring outside the northern beaches, including in Wollongong," she said.
"There are nearly 50 public transport routes identified as possible exposure locations in various parts of Sydney.
"Additionally, given the gatherings of families and friends we see at this time of year, there are also other potential opportunities where transmission may have occurred in private residences or functions across greater Sydney over the Christmas period."
Canberrans have also been reminded not to travel to Greater Sydney, or any other COVID-19 affected areas, and to reconsider travel to NSW more broadly.
"We are keeping a close watch on what is happening in NSW but the situation can change quickly," Dr Coleman said.
"We know the outbreak in NSW has already affected many holiday plans, but with new affected locations being identified daily, people are advised to reconsider their need to travel at this time.
"For those in COVID-19 affected areas of NSW, we also ask that you respect the public health direction that has been put in place and do not travel to the ACT."
NSW reported 18 new cases involving community transmission on Wednesday, with six linked to a new cluster in Sydney's inner-west.
The ACT reported no new COVID-19 infections and has only one active case.