Stay-at-home orders are being tightened in three Sydney council areas, retail is being restricted and construction paused as NSW records a COVID-19 death and 111 new community cases.
From 11.59pm on Saturday, Fairfield, Canterbury-Bankstown and Liverpool council residents are not allowed to leave their local government areas until July 30.
At least 80 per cent of cases have come from the southwestern area, Premier Gladys Berejiklian said on Saturday.
The only people from those areas allowed to leave their locality are those who work in health and emergency services, including aged and disability care.
Tougher restrictions also apply to the entire Greater Sydney lockdown region.
From Sunday, only critical retailers such as supermarkets, pharmacies and banks will be allowed to open.
Other retailers will have to operate with 'click and collect' or takeaway.
Construction sites, large or small, will be shut.
All office workers and others working from home should not be pressured to go in to work, with employers to potentially incur a $10,000 fine if they push staff to attend.
Ms Berejiklian also told Sydneysiders not to carpool with anyone.
She acknowledged many people would be upset by the new restrictions, but said the decisions had not been made lightly.
The data modelling based on more than 400 exposure sites indicated everyone in Sydney is at risk, the premier said.
She defended the measures taken to curb the outbreak so far, saying they had prevented "thousands and thousands" of cases and the further restrictions were a "no-regrets policy".
The harsher measures were prompted by the persistent numbers of people infectious in the community before they were diagnosed.
At least 29 of the 111 new cases announced on Saturday were infectious before going into isolation, a number authorities say is too high.
"We are seeing some cases still diagnosed late, but we need to see that number get down, it is far too high and that is the basis for why we have recommended much more extensive actions to reduce those interactions," NSW chief health officer Kerry Chant said.
Workplaces are a key area where new infections are being seeded, she added.
Dr Chant defended the decision to wait until now to implement harsher directives, saying the time lag in learning about infections was a challenge and referring to her efforts so far in urging workplaces to "do the responsible thing".
The chief health officer was also keen to dispel the myth that it wasn impossible for asymptomatic people to transmit coronavirus, saying a person can be infectious when asymptomatic.
Dr Chant confirmed a Sydney man in his 80s died from the virus on Friday.
Asked about an infected mother who has been separated from her newborn at Nepean Hospital, Dr Chant said: "I can't imagine how difficult the circumstances (are) of giving birth knowing that you are COVID-positive."
Meanwhile, NSW police issued 162 fines in the 24 hours to Saturday to people flouting the lockdown.
Commands are ramping up enforcement in the three southwestern local government areas that are going into an extra-strict lockdown.
Residents were assured on Saturday that government agencies would mobilise between now and July 30 to provide them with supplies and services as needed.
A record 82,000 people came forward for COVID-19 testing on Friday.
The 111 cases recorded on Saturday follows 97 announced on Friday.
Australian Medical Association president Omar Khorshid endorsed the stricter measures, saying the state would only "win" against the virus if everyone was on board.
"Sydney facing its greatest challenge over next two weeks. Win: return to 'normal' life. Lose: 6 months of heavy restrictions, chaos and closed borders with illness for many, death for some," he tweeted.
A full list of NSW exposure sites can be found at health.nsw.gov.au