There have been no new cases of COVID-19 diagnosed in the NSW Hunter despite thousands of tests, but it is still too early to "breathe easy".
Close to 66,000 swabs for COVID-19 have been done in the Newcastle LGA in the past three weeks, with recent closures of local hotels and venues prompting more younger residents to come forward for testing.
"Clearly, these are high risk venues," Dr David Durrheim, Hunter New England Health public health physician, said.
"Often the background noise is loud and people have to speak very loudly which can project the virus further, and if you can't keep the 1.5 metres, the opportunities for the virus to find another victim are rather high."
Testing numbers in Newcastle rose from 22,251 in the week beginning July 20, to 25,746 in the week of August 3. Tests for people in the 20-to-29 age group rose from around 100 a day, or lower, from July 24, to 500 on August 6.
Similarly, the number of tests on people aged 30-to-39 rose from close to 100 a day on July 24 to more than 300 tests on August 6.
Dr Durrheim said his team was still investigating the source of infection for the 15-year-old St Pius X Adamstown student, and related family cluster, that was identified in Newcastle last week.
Until the source of infection was known, Newcastle would be considered an "area of suspicion".
"We have to be on the alert that this may have been community transmission, and when there is a mystery around the source, we have to be prepared that there may have been other people infected as well," he said.
"We know that while there is movement between Newcastle and Sydney that the opportunity for reintroduction of the virus is possible."
Dr Durrheim said we could only start to "breathe more easily" after at least two weeks of no local cases.
"Unfortunately the incubation period for this virus keeps us in suspense for a long time," he said. "To be really certain there is no local transmission, we usually take two incubation periods, which is four weeks.
"The more days that tick over before we have another case, the easier we will all breathe - but it is far too early to become confident we won't get any additional cases."
A single negative test could not rule out COVID-19 if symptoms developed.
"The average to the onset of symptoms is between five and seven days, but can be as long as 14 days," he said.
"So anybody who in the next two weeks develops sniffles or a sore throat or a cough, and has particularly been to any of those locations we specified, really should get themselves tested. We are not through the woods yet.
"Developing symptoms or a fever should prompt one to be tested, even if you have previously tested negative."