NSW records 15 locally acquired COVID-19 cases on Monday.
Sydney's Northern Beaches cluster has increased by 15 on Monday.
NSW Premier Gladys Berejiklian said all the locally acquired cases to 8pm on Sunday were linked to the Avalon outbreak, bringing the total number in the cluster to 83, up from 63 on Sunday.
More than 38,000 tests were conducted.
NSW recorded 15 locally acquired cases of COVID-19 in the 24 hours to 8pm last night, and an additional eight cases in returned travellers in hotel quarantine. pic.twitter.com/BBkUgXZELD— NSW Health (@NSWHealth) December 21, 2020
Berejiklian said her government will consider its position in relation to what Christmas and the next few days will look like beyond midnight Wednesday morning, "but obviously it is an ongoing brief".
She said the final decision about Christmas Day would come on Wednesday morning.
"I thank people again for coming forward and getting tested. I thank people for respecting the health orders and restrictions. It is evident people are doing what we asked them to do," she said.
"In terms of mask-wearing, please make sure, if you in an indoor setting, obviously on the Northern Beaches it's more paramount, but if you're catching public transport, you need to be wearing a mask. If you're going grocery shopping or indoor shopping, in a mall or anywhere else, you need to be wearing a mask... Don't think you're immune. This can affect any of us."
NSW Chief Health Officer Dr Kerry Chant said NSW Health was still unsure of the source of the spread in the community.
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NSW recorded another 30 confirmed COVID-19 cases on Sunday, with 28 of those already linked to the growing Avalon cluster on Sydney's Northern Beaches.