The escalating situation has prompted NSW to pivot its vaccine rollout strategy, with AstraZeneca to be offered at mass vaccination clinics to people aged over 40.

Premier Gladys Berejiklian signalled that further financial support for struggling Sydney businesses was on its way, as she conceded that it was "almost impossible" for the city's lockdown to be lifted as planned on Friday.

Daily case numbers in Sydney's latest outbreak topped triple figures for the first time on Monday, after 77 new infections were recorded on Sunday.

A total of 63 people have been hospitalised, including 18 in intensive care. Four people were on ventilators as of 11am on Friday.

NSW authorities remain most concerned about the high number of people who are infectious while in the community.

That number was 34 in the 24 hours to 8pm last night, while the "isolation" status of a further 18 people remains under investigation.

Ms Berejiklian indicated that bringing that number close to zero would be the key to beating the outbreak and lifting Sydney out of lockdown.

The bulk of the new cases are in Sydney's south-west, with the Fairfield, Liverpool and Canterbury-Bankstown council areas of most concern for authorities.

In response to the evolving crisis, NSW Health will now administer the AstraZeneca vaccine at its mass vaccination clinics to people aged over 40. It will also allow pharmacists to do the same.

People aged under 60 who wanted AstraZeneca had been previously been encouraged to consult with their GPs, so they could take the time to discuss the extremely small blood clot risks.

But NSW Chief Health Officer Kerry Chant said the threat posed by the growing outbreak warranted a change in advice.

"The current risk situation had changed dramatically," she said.

"Under the current situation, because we actually have Covid and the Delta strain circulating, it then means that your individual risk of acquiring the strain is very much different than it would have been a month or so ago when your community risk would have been very low."

As shuttered businesses continue to cry out for support, Ms Berejiklian said an announcement on a new financial assistance package was "imminent".

The premier said she and NSW Treasurer Dom Perrottet had held high-level talks with the Morrison government about Commonwealth assistance, but did not provide further details.

Sydney's fast-growing outbreak on Sunday prompted the Victorian government to slam its border shut to NSW, as well as the ACT.

Queensland is holding fire on a hard border closure to all of NSW, but officials were on Monday morning foreshadowing that a travel ban could be imposed if the situation worsens.

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"My message to Queenslanders is if you are in those areas [in Sydney], come home," Queensland Premier Annastacia Palaszczuk said.

"I can't be any clearer. Please, even if you are in regional parts of NSW, we are monitoring that very closely and things can change.

"My message to Queenslanders is to think seriously, long and hard, about what you are doing and if you can, come home."

Queensland's border remains opens to the ACT.

There was no mention at Monday's morning's press conference if Queensland would followed the lead of Victoria and South Australia and ban travelers from the ACT if it shut its border to all of NSW.

More to come.

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