Calls placed to the helpline at 9am on Monday went straight to a busy signal.

Health Minister Rachel Stephen-Smith said: "My apologies to everyone who's waiting and thank you for your patience."

"Everyone's got their heads down at the moment and they're really trying to get that information out so they can reduce the need for people to call," Ms Stephen-Smith told ABC radio.

Callers to the station reported being in a queue of 3000 calls to the line before 9am; the line opens at 8am.

However, the ACT Minister for the Arts, Business, Multicultural Affairs, Human Rights, Tara Cheyne, said queues were only in the hundreds.

Canberrans have been told to check the ACT government's COVID-19 website before calling the helpline.

An ACT government spokeswoman said wait times were due to line capacity rather than staffing levels.

A dozen extra staff were brought on from Sunday night to take calls, with 45 of 65 incoming lines dedicated to COVID-19 queries, she said.

ACT Health corrected a quarantine restriction mistake on Monday morning, clearing the way for Canberrans to travel to and from the south coast for Christmas.

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Health officials initially included the lllawarra-Shoalhaven region in their list of areas to avoid when announcing changes to coronavirus travel advice on Sunday night.

The new measures were put in place in an attempt to limit the spread of the northern beaches outbreak in Sydney, with Canberrans told to avoid travel to greater Sydney, the Central Coast, Wollongong, the Blue Mountains and Shoalhaven.

The Wollongong local government area remains in the list of affected regions.

Any ACT residents returning from those regions must alert authorities and enter into 14-days quarantine on arrival.