The government had allocated a 'green zone' around the harbour foreshore including the Opera House just for the workers, who were invited to attend from across the state.

"Unfortunately, we're going have to cancel that," Premier Gladys Berejiklian said on Monday.

"It's too much of a health risk having people from the regions and from Sydney and from broader regional areas congregate all in the CBD."

Restrictions for greater Sydney and regional NSW will remain largely unchanged over the New Year's Eve period, with the only difference being that outdoor gatherings in greater Sydney can have up to 50 attendees.

NSW recorded five locally acquired cases of COVID-19 in the 24 hours to 8pm, with an additional nine cases in returned travellers in hotel quarantine.

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Four of the locally acquired cases are linked to the Avalon cluster. Investigations continue into the source of this cluster, which now numbers 126.

The fifth local case is linked to a previously reported case on the Northern Beaches whose source of infection is not yet linked to the Avalon cluster and remains under investigation.

All five locally acquired cases reported had previously been identified as contacts of known cases and were in isolation.

This brings the total number of cases in NSW to 4,683 since the beginning of the pandemic.

"Sadly, a man in his 70s died earlier this week from respiratory complications following a COVID-19 infection diagnosed in March," a NSW Health statement said.

"He was a household contact of a locally acquired case. Although his death is considered to be related to COVID-19, he had recently tested negative, was no longer infectious and posed no risk to the community. NSW Health extends its sympathies to his family."

There were 15,364 tests reported to 8pm Sunday night, compared with the previous day's total of 23,933.

NSW Health thanks the community for their excellent response to the call for testing, and for following public health advice.

"Every person who is tested plays an important role in helping to contain the spread of COVID 19.

"However, testing numbers have fallen in the post-Christmas period, and it is vital that people throughout NSW continue to come forward immediately if they have even the mildest of symptoms."

The changes in outdoor gathering sizes in Greater Sydney comes after NSW Police broke up several large gatherings during the Christmas holiday period.

Police fined 11 young people at a party at North Bondi for failing to comply with COVID-19 rules.

At least 40 people were at the party and most ran away when officers arrived just after 11pm on Boxing Day.

Two women and nine men were fined $1000 each because indoor gatherings were limited to only 10 visitors.

Another man was fined on Christmas Day after he allegedly went from an unauthorised party at Bronte Beach to a gathering at Centennial Park that also exceeded coronavirus restrictions.

A Newtown restaurant was fined $5000 after police attended on December 23 and learned the owner did not have a COVID-safe plan.

Police said there were 27 people too many inside and a crowd outside.

- With Australian Associated Press