NSW’s chief health officer fought back tears as she pleaded with Sydneysiders to stay home and follow tough new rules designed to help stem the state’s devastating COVID outbreak.

Dr Kerry Chant – who has been absent from some recent daily briefings – was clearly emotional as she announced the latest fatalities from the virus on Friday.

There were four more COVID deaths in NSW on Friday – two women in their 80s and two men in their 70s and 80s.

“I do not want to be standing here every day, announcing these high rates of hospitalisations, and these deaths,” Dr Chant said.

“Every one of these deaths is someone’s mother, father, grandmother, grandfather. And I want to see those deaths as low as possible.”

All of NSW is locked down and restrictions will be tightened further on Monday. Masks will become compulsory whenever leaving hom across NSW, while the 12 local government areas that account for most COVID cases will face a daily curfew.

The lockdown of greater Sydney and surrounds has also officially been extended until at least the end of September, as health authorities battle to contain the virulent Delta strain.

NSW had 642 new local cases on Friday, prompting the imposition of the stricter measures. They come despite Premier Gladys Berejiklian resisting more stringent rules – including mandatory masks and a curfew – for several weeks.

Asked on Friday if she had pushed for such measures earlier, Dr Chant said only that she was “totally committed to these additional measures”.

She also addressed speculation amid differences with the state government about how to handle NSW’s spiralling COVID emergency.

“I can confirm that I have not threatened to resign at any point,” she said.

“I am so committed to seeing this outbreak behind us. I am so committed to doing all I can as part of a broader team.”

In another change as the rules tighten in NSW, permits will be required from Saturday for anyone leaving greater Sydney for regional areas.

Authorised workers from the 12 local government areas of concern will have to carry Service NSW permits declaring they cannot work from home. Anyone entering one of the LGAs must also carry a worker permit.

A 9pm-5am curfew will also apply in the 12 LGAs, which are Bayside, Blacktown, Burwood, Campbelltown, Canterbury-Bankstown, Cumberland, Fairfield, Georges River, Liverpool, Parramatta, Strathfield, and some suburbs of Penrith.

Ms Berejiklian and Dr Chant have repeatedly and vehemently denied that curfews are useful as a public health measure.

“The evidence for curfews is not strong,” Dr Chant said on Friday.

“But the Police Commissioner and I considered that because of the intelligence we were getting, it may be effective, and may assist.

“I personally do not want to leave any stone unturned in terms of the things that we are doing to bring this under control.”

People in those areas will also have their daily exercise limited to just one hour, and NSW Police will be able to lock down entire apartment blocks due to COVID-19 cases.

Masks will also be mandated at all times – indoors and outdoors – across NSW from Monday, unless exercising. Ms Berejiklian said that was primarily to aid police.

“It makes it easy for them to make sure that everybody is sticking to the rules – so this means mask-wearing outdoors unless you’re exercising,” she said.

COVID-19 vaccinations for all NSW healthcare workers will also be mandated by the end of September, and for childcare workers and disability support workers in the council areas of concern by August 30.

That gives childcare and disability support workers just 10 days to receive their first jab.

Greens health spokesperson Cate Faehrmann welcomed the change but said it should’ve come sooner.

Elsewhere, 80 healthcare workers at Sydney’s St George Hospital are this week isolating due to COVID exposure in the oncology ward.

The Berejiklian government is still looking at ways to give vaccinated people more freedom in September when the state has reached six million jabs, but is yet to outline this plan.

Dr Chant said case numbers would have to come down before any restrictions were eased.

“I do not think anything about the Premier’s comments is anything that recognises the escalating case numbers and the situation we are in,” she said on Friday.

The Australian Medical Association warned the NSW government to not “take any chances” by easing any restrictions.

“We’ve seen in NSW and overseas that once the Delta virus takes hold, it is very hard to contain,” AMA President Omar Khorshid said.

The state broke another record for daily vaccinations on Wednesday, with 132,439 people in NSW receiving the jab.

Some 55.2 per cent of people over 16 in NSW have had at least one dose of the vaccine, with 29.32 per cent fully jabbed.

-with AAP