The increased demand comes after vaccination bookings opened up for children aged five to 11 on Monday. To book, people need to call 5124 7700, and request a call back. Their place will then be held in the queue.

People have reported waiting up to two days for a call back to book their child in to be immunised.

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An ACT Health spokesperson said the directorate was "still experiencing very high volumes of calls".

"All callers now need to leave a call-back request. Call backs are being made in order of call-back requests received," they said.

Meanwhile, COVID-19 testing centres have reached capacity, with long lines and more than four-hour estimated wait times for most of Wednesday.

The ACT reached a daily record of 58 new COVID-19 cases as of 8pm, Tuesday.

Since vaccination for children aged five to 11 opened, 5675 bookings have been made, to close of business on Tuesday.

"There are plenty of bookings available, and we are asking people to be patient," the spokesperson said.

"We are expecting a good supply of vaccine when it arrives, so everyone that wants a vaccine for their child will be able to get one."

On Twitter, ACT Health Minister Rachel Stephen-Smith thanked the community for their patience, "while our team make their way through thousands of calls".

Currently, the earliest bookings available are from January 14.

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