NSW has recorded 105 new COVID-19 cases as residents in Greater Sydney adjust to tougher lockdown restrictions designed to curb the rate of infection.

Premier Gladys Berejiklian said 27 of the new cases had been infectious while in the community.

"That's the number that worries us the most, we've seen that number crop up day in and day out," she said on Sunday.

The state is yet to see a significant drop in case numbers despite some form of lockdown conditions in the capital for three weeks.

Ms Berejiklian said she expected a lag of between five or six days until case numbers began to drop as a result of the latest restrictions.

"We are throwing everything at this, we want to come out of this lockdown as soon as possible," she said.

The majority of Sunday's cases are concentrated in southwestern Sydney, with 69 found in the Fairfield local government area.

However Chief Health Officer Kerry Chant said residents had to be vigilant no matter where they were in Greater Sydney.

"Every time you leave your house, it is critical that you assume you are coming into contact with COVID," she said on Sunday.

Residents are barred from leaving three council areas while all but critical retailers across Sydney are closed.

Stay-at-home orders have been tightened in Fairfield, Canterbury-Bankstown and Liverpool with locals not allowed to leave until July 30.

Initially there were only exceptions for workers in health or emergency services, however the list has been expanded considerably to include retail workers in shops permitted to open as well as teachers and freight drivers, among others.

Asked about the shifting guidelines in the wake of the major announcement, Ms Berejiklian thanked residents for their patience and said "comprehensive" information is now available.

"I'm not embarrassed to say that in public life yesterday was probably the most difficult day I've had personally," she said.

The southwestern lockdown has prompted a harsh response from some within the medical community.

The Doctors Reform Society says enough Pfizer vaccine to administer to all 600,000 adults who live within the three municipalities should be provided within the next fortnight.

Tougher restrictions now apply across the entire Greater Sydney region including the shutting down of construction sites large and small.

Supermarkets, pharmacies, banks and few other retailers are allowed to open and must operate with 'click and collect' or takeaway.

All office workers and others working from home should not be pressured to go in to work, with employers to face a $10,000 fine if they push staff to attend.

With data modelling based on more than 400 exposure sites indicating everyone in Sydney is at risk, the premier said the harder line was needed.

On Saturday 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.

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 full list of NSW exposure sites can be found at health.nsw.gov.au

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The Australian Olympic track and field team has had a COVID-19 scare, with a member of the support staff recording a positive test.

The staff member is in quarantine, pending a final test later on Sunday.

Australian team chef de mission Ian Chesterman said in Tokyo that the staff member returned a weak positive test.

Two further tests have come back negative.

The bulk of the Australian athletics team is at a pre-departure training camp in Cairns, with other members of the squad in Europe and Sydney.

Two days ago, tennis star Alex de Minaur had to pull out of the Games after testing positive to coronavirus.

Image: Supplied 

Labor is pressuring the Morrison government to rethink its economic support programs amid a growing virus crisis as the country's two major cities are in lockdown.

The NSW state government tightened its lockdown measures, which came into play from midnight and include stopping any construction work.

"Come tomorrow, people would have been going to work in most instances and they can't go to work," Labor frontbencher Chris Bowen told Sky News' Sunday Agenda program.

"There will be a very big crisis when it comes to families' budgets across our area and the economic package that Scott Morrison has delivered does not cut the mustard."

He said the support package that is being provided is complex, confusing and difficult to access the information.

"I didn't have to explain JobKeeper to people. JobKeeper had the benefit that it kept people in touch with their employer, it kept the employment link open and alive and that doesn't happen at the moment," Mr Bowen said.

The government has repeatedly said it will not return to the JobKeeper wage subsidy scheme which ended in March.

Some 12 million Australian residents are under COVID-19 lockdown, with the rest living with some form of travel restriction.

NSW reported 111 new community cases of the virus on Saturday along with the death of a man in his 80s, the third fatality in this current outbreak.

Lockdown restrictions in NSW were tightened again - the third time in as many weeks - as the Victorian government boasted its "go hard and go early" strategy had been vindicated by the spiralling situation in NSW.

Although 18 of the 19 new cases in Victoria were not in insolation for the entirety of their infectious period, on average each only spent 1.7 days in the community before their infection was picked up.

But Australia is not alone in this battle against COVID-19.

Trade Minister Dan Tehan is currently in South Korea, having also been in Singapore and Japan as part of a tour of Australia's trading partners.

"They are all at the moment trying to suppress the Delta strain like we are in Australia," Mr Tehan told Sky News.

"One of the very interesting discussions has been how we plan for life once we have dealt with the virus, suppressed it, and how we begin to open our economies and they are are looking to next year, hopefully, to be able put that in place."

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Business and unions are concerned about the closure of the construction industry in NSW and the "massive" impact it will have on the economy.

Economists were already estimating the cost of the twin shutdowns in Australia's two major cities at $10 billion even before the NSW government tightened restrictions further on Saturday.

Such concerns came as NSW reported a further 105 new virus cases on Sunday, as well as the death of a woman in her 90s, the fourth fatality in this breakout.

The Greater Sydney lockdown at this stage is due to end on July 30.

In Melbourne, which is in the middle of a snap five-day shutdown, 17 cases were reported.

Victorian Premier Daniel Andrews told reporters it was too early to say whether his state's lockdown will end as planned.

Business Council of Australia chief executive Jennifer Westacott said the new NSW restrictions, including the closure of the construction industry, were a big blow to the economy.

"The shutdown of construction will have a massive economic impact because this is a sector with a long tail through the economy," Ms Westacott said.

"We have to find a way through on construction as a matter of urgency because there are big financial and health and safety impacts that flow from a sector-wide pause."

CFMEU NSW secretary Darren Greenfield said the decision will affect hundreds of thousands of workers across the industry and supply chains.

"The NSW and federal governments need to ensure any emergency payments and other support measures are made available to affected workers and their families without delay," he said.

Federal Labor is also pressuring the Morrison government to rethink its economic support programs, demanding a return of the successful JobKeeper wage subsidy that ended in March.

"Come tomorrow, people would have been going to work in most instances and they can't go to work," Labor frontbencher Chris Bowen told Sky News' Sunday Agenda program.

"There will be a very big crisis when it comes to families' budgets across our area and the economic package that Scott Morrison has delivered does not cut the mustard."

He said the support package that is being provided is complex and confusing and it's difficult to access the information.

"I didn't have to explain JobKeeper to people. JobKeeper had the benefit that it kept people in touch with their employer, it kept the employment link open and alive and that doesn't happen at the moment," Mr Bowen said.

The Morrison government has repeatedly said it will not return to the JobKeeper scheme.

However, the government is providing $3 million to ensure young Victorians can access mental health support if and when they need it during this lockdown.

The funding will be matched by the Victorian government and delivered through headspace, helping meet the critical demand for youth mental health services across the state.

"This is a tough time for our young Australians and we want them to know that they are not alone, which is why we're putting more health professionals on the ground to meet increased demand," federal Health Minister Greg Hunt said.

The government is also making available significant quantities of personal protective equipment to a number of GPs, community pharmacies and other healthcare providers across multiple Victorian areas, including Greater Melbourne.

Th equipment includes up to 725,000 surgical masks and 175,000 pairs of gloves, gowns and googles.

"These packages will assist to further suppress the COVID-19 infection rate occurring across Melbourne and builds on the recent commitment to support NSW," Mr Hunt said.

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