Fragments of the COVID-19 virus have been detected in Dubbo's sewage, Premier Gladys Berejiklian has announced, while the Hunter will enter a week-long lock down.
Fragments of the virus were detected in sewage samples taken at Dubbo and Armidale and people in those regions are urged to continue to get tested.
"The levels in sewage have become higher and we are concerned there may be active cases in Armidale," Dr Kerry Chant said on Thursday morning.
"Obviously we are very concerned about regional NSW and that's why we have protections in place for regional NSW in terms of mask-wearing.
"I know that there's probably been lots of reports and police have responded lots of times to communities highlighting where people are in breach.
"We are very concerned and that's why no-one can be complacent."
All Hunter LGAs including Dungog will fall under the harsher restrictions as seen in greater Sydney from 5pm on Thursday.
It follows cases at schools in Maitland and Lake Macquarie, as well as an exposure at University of Newcastle's Auchmuty library.
Ms Berejiklian said testing overnight had revealed there were "some cases" in the Hunter but did not immediately specify how many had been detected.
NSW has recorded 262 cases in the past 24 hours.
45 infectious were infectious in the community, while five people have died in the same period; three in their 60s, one in their 70s, and one in 80s.
Dr Chant said five people were being cared for in the Hunter and investigations were underway, but they believed the source of infection was a Lake Macquarie gathering.
"We now think that the source extended from a gathering on Blacksmiths beach on Friday night," Dr Chant said.
Dr Chant confirmed two Maitland Christian School students were among those infected.