NSW Premier Dominic Perrottet announced the mask mandate on Thursday. Photo / NCA NewsWire
New South Wales has set a new record for the highest number of daily cases since the pandemic began as it reached 6288 new cases on Christmas Day.
The Australian state's cases have continued to increase since Omicron started to spread and restrictions were eased.
On Friday, there were 5612 new infections and a woman in her 90s from southwestern Sydney died from the virus at St George Hospital.
New cases leapt by almost 2000 from Wednesday, when 3763 infections were reported.
It comes as Queensland also hit a new record, with 765 new Covid-19 infections for Christmas.
Victoria recorded 2108 new Covid-19 cases, bringing the total number of its active cases to 17,599.
From Christmas Eve, residents in NSW have been required to wear masks indoors and check in to stores and venues.
The rules were put back in place in response to Omicron's influence on the daily case numbers and are expected to remain until January 27.
Premier Dominic Perrottet announced the new rules on Thursday, saying they were "modest" and "cautious".
"As we move through this holiday period to the end of January, the system is in a very strong position," he said.
While Omicron is much more transmissible, chief health officer Kerry Chant said the strain appeared less severe than Delta.
"The early signs are encouraging," she said.
There are 388 people in hospital, including 52 in intensive care.
There were 149,261 tests conducted in the past 24 hours.
Around 95 per cent of residents aged 16 and over have had at least one dose of a Covid-19 vaccine, while 93.5 per cent are double jabbed.
There are also 78.3 per cent of people aged 12-15 who are fully vaccinated.
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