Contact tracers now are working to determine where the case has been and who they have been in contact with.

The Mid North Coast has remained COVID-free for more than 475 days despite being surrounded by a ring of positive cases from Greater Sydney through to the Hunter-New England and the North Coast.

A case, who contracted the virus from Newcastle, is also isolating at home in Forster to the south.

NSW has recorded its worst day yet since the pandemic began with 633 new COVID cases and three more deaths.

A man in his 60s who was a patient in the Liverpool Hospital geriatric ward has died as well as two men in their 70s who both died at Nepean Hospital.

Of the new cases, 550 were from south-western and western Sydney with the vast majority younger people.

Sixty-two were infectious in the community, 30 were partly isolating and the status of 447 cases is under investigation.

Deputy Premier John Barilaro said cases in regional NSW remain a significant concern and that is where the focus is.

Mr Barilaro said the Kempsey case was confirmed after last night's reporting period. There is another on the Central Coast.

Armidale and Tamworth have recorded no new cases.

Read more:

Hunter-New England recorded 15 new cases. There were 10 new cases in Newcastle, two in Maitland and three in Lake Macquarie.

Sewage surveillance testing continues to pick up virus fragments in Yamba, Orange, Wollongong and Bathurst.

Sewage surveillance on the Mid North Coast continues.

Premier Gladys Berejiklian announced the disturbing escalation in the case numbers on Wednesday (August 18), warning the state had "not seen the worst" of the outbreak.

"Just stay home," she said.

She said most transmission was occurring in workplaces and households.

The government remains concerned about indigenous communities in western NSW and urged anyone who had been in Wilcannia to come forward for testing.

She also said West Dubbo continued to be an area of concern.

Check out your postcode's vaccination rate details here

"I can't express enough my level of concern," chief health officer Kerry Chant said of the 633 new cases.

"Whilst vaccination will be an aid and essential... our vaccination coverage at the moment is far too low. We need to do everything we can to not come in contact with anyone."

"We have a collective responsibility to stop seeing those deaths and hospitalisations increase.

"Please be cautious wherever you are in the state."

Dr Chant said there had been 23 new cases of COVID in western NSW, with 17 in Dubbo and one at Bourke, bringing total case numbers to 139.

There are 462 people in hospital, with 77 in intensive care.

Schooling will be done from home in most cases.

Masks must be worn indoors (not including the home) and in outdoor settings where you cannot socially distance from others. Anyone who leaves their home must carry a mask with them at all times.

From August 16, 2021: NSW under 5km from home outside LGA rule and other additional restrictions

The Mid North Coast Local Health District is vaccinating its staff and eligible members of the community when appointments become available.

The local health district will move its COVID-19 vaccination clinic from Port Macquarie Base Hospital to 35 Grant Street, with the new clinic expected to open on Tuesday, August 17.

Go to the online COVID-19 vaccine eligibility checker to find out when and where you can receive a COVID-19 vaccine.

You can also speak with your local participating pharmacist or GP about the vaccine that is right for you.

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: