But the NSW government still hopes the regions can drive COVID-19 cases close to zero and exit lockdown sooner than Sydney.

There were 25 new local COVID-19 cases reported in western NSW to 8pm on Wednesday, taking the total for the region to 167.

Five cases were also uncovered in Hunter New England, one in the Central Coast, one in the Mid-North Coast and one in Southern NSW.

As a result, Premier Gladys Berejiklian says lockdown settings in the regions will be extended to August 28.

"Things are settling down in other parts of regional NSW, which is positive, but concerns remain for western NSW," Ms Berejiklian told reporters on Thursday.

"There are vast areas of regional NSW where there are not any cases but everybody would appreciate and expect us to take a precautionary response given we have the opportunity to get down to zero cases."

Authorities also say the Central Coast and Shellharbour regions will be reclassified as "regional areas" for the yet-to-be-implemented regional NSW travel permit.

They were earlier included in Greater Sydney's lockdown.

Deputy Chief Health Officer Marianne Gale said three cases were uncovered overnight in Wilcannia in far west NSW. Anyone who has been in or near Wilcannia in recent days has been told to seek testing.

However, western NSW residents have reported major delays in test results. In Cobar, some residents had waited five or six days for results.

One woman who was in Dubbo during times of concern and then displayed symptoms said the mobile number she was told to text for results was twice replaced with a new number.

When she called a phone line for people waiting more than three days for test results, it either went to voicemail or cut out.

"A lot of people from our town travel out of town quite regularly, especially to Dubbo," the Cobar woman, who asked not to be identified, told AAP.

"If we had cases here it would be different and we would be considered a priority, whereas at the moment we don't seem to be a priority.

"There are multiple people off work pending results and that for some has been a full week off work using their own sick leave."

Sewage surveillance has uncovered COVID-19 fragments in wastewater in Forster, Bateau Bay, Mittagong and Yamba, Dr Gale says.

Deputy Premier John Barilaro also said two cases had been uncovered in Queanbeyan, near the NSW-ACT border. The ACT is also under lockdown as it battles a COVID-19 outbreak of at least 83 people.

"This is why it is right to stay in front of the curve, in front of the spread, and keep regional NSW in lockdown," Mr Barilaro said.

"My message is to stay vigilant and get tested if you have symptoms."

The Dharriwaa Elders Group in Walgett - which Ms Berejiklian has said is "of enormous concern" - has called for more data on rates of COVID-19 vaccination of Indigenous people.

Australian Defence Force troops arrived in Dubbo and Newcastle on Wednesday to assist police as the crisis escalated.

The ADF will work with health authorities to help vaccinate and test people, conduct welfare doorknocks and undertake compliance checks.

Australian Associated Press