But daily infections are unlikely to top 2000 per day, the NSW premier says, and the state's 1550-bed ICU surge capacity is expected to bear the load of admissions.

NSW reported 1281 new locally acquired cases of COVID-19 and five deaths in the 24 hours to 8pm on Sunday, taking the toll for the current outbreak to 131.

The five deaths recorded in the 24-hour reporting period include a man in his 90s, two women in their 80s, a man in his 60s and a woman in her 50s.

Modelling conducted by the Burnet Institute for NSW Health and published on Monday shows daily COVID-19 infections will increase until mid-September, with cases forecast to hit 1100 to 2000 per day.

Vaccine-acquired immunity along with the state's strict lockdown would then begin to bend the curve.

As cases accumulate, hospitalisations - COVID-related or otherwise - will peak at about 3400 in late October, with COVID-related ICU admissions hitting 560 in early November. Overall ICU occupancy could approach 950 beds.

But Premier Gladys Berejiklian says an intensive care surge capacity of 1550 beds - lower than the previously-announced 2000-bed capacity - will likely hold up, even if patients need to be transferred to distant hospitals.

She warned the modelling was predicated on several variables including compliance with lockdown and no super-spreading events.

"You may be moved to a different hospital than the one closest to your home ... but the bottom line is anyone who needs care will receive it," Ms Berejiklian said on Monday.

"Our surge capacity, we estimate, is in excess of what we'll need."

"The biggest determinant of whether someone ends up in ICU is whether or not they're fully vaccinated and that's why every day, every week that goes past and our rates of vaccination increase, that puts less pressure on our system."

Ms Berejiklian has pledged to restore some freedoms for fully jabbed residents upon 70 per cent double-dose vaccination coverage, expected in mid-October.

There are 1071 COVID-19 patients in NSW in hospital, with 177 in intensive care and 67 on ventilators.

Nepean Hospital intensive care doctor Nhi Nguyen reiterated that staffing levels were the most important variable in intensive care, rather than beds or ventilators.

Intensive care training for nurses has been boosted throughout the pandemic while other healthcare workers such as operating theatre nurses, emergency department nurses and coronary care nurses were also well trained.

Some 2000 nurses have been upskilled to work in intensive care.

Dr Nguyen said NSW Health was approaching its intensive care system as "one whole unit".

"We have a very good idea where every ventilator is, we have registers about our staffing, we are sharing resources ... importantly, we have really amazing visibility of where all our patients are across the health system," Dr Nguyen said.

"We know there are nursing and medical staff who will feel a little uncomfortable with what they are being asked, but I'm confident we have such a well-connected and supportive environment that patients will continue to get care."

Meanwhile, thousands of essential workers in Sydney's 12 local government area COVID-19 hotspots have been given a two-week extension on an order to get their first vaccination if they want to work outside those areas.

The government has given workers another fortnight to get their first vaccine dose but they have to book a vaccination appointment by Wednesday.

Australian Associated Press