NSW's deputy premier has flagged the possibility that people who wish to travel to regional areas might need to be double-vaccinated once the state opens up.

The western NSW town of Dubbo remains the epicentre of the state's regional COVID-19 outbreak.

Deputy Premier John Barilaro said 18 of the 23 new cases in the Western Local Health District were in Dubbo, which is "the heart and centre" of the virus.

More than two-thirds of cases in the region are in the Indigenous community.

Australian Medical Assistance Teams are offering vaccinations to people living in isolated homes in addition to the hubs run by Defence, the Royal Flying Doctor Service, as well as Indigenous health services.

There were also four more cases in Orange and one in Brewarrina recorded in the 24-hours to 8pm on Wednesday.

"Again, I call out to those communities to get tested," Mr Barilaro said on Thursday.

"It's where the concentration of the outbreak is in rural and regional NSW."

In the far west, there were five new cases - four in Wilcannia and one in Broken Hill.

Mr Barilaro also flagged the possibility that Sydneysiders who wish to travel to the regions might need to be double-vaccinated once the state opens up.

"We will be looking at the data to make sure we protect those vulnerable communities, our regional and rural communities," he said.

"But why wouldn't it be a double vaccination requirement?

"If the endgame is for everybody to be vaccinated, that's something that will be put into consideration," he said.

There are also concerns about the Illawarra region, where numbers are rising with 22 new cases - 15 in the Wollongong local government area and seven in the Shellharbour LGA.

NSW Chief Health Officer Kerry Chant said seven new cases in the Central Coast region were also causing concern.

"Three of those are linked to a previously notified case but unfortunately all seven were infectious in the community," she said.

Of the record 1288 locally-acquired cases reported for the entire state, 82 were in the Nepean Blue Mountains region and four were in the Hunter New England region.

NSW Health's sewage surveillance program has detected fragments of the virus at treatment plants in Bega and Cooma in southern NSW, Bomaderry on the south coast and in the Illawarra Shoalhaven district.

But there are no known cases in those areas and residents are being urged to monitor for the onset of symptoms, and if they appear get tested and isolate until a negative result is received.