The police dog unit tracked down people who fled an illegal gathering in a Jesmond garage on Saturday evening.
Police issued eight public health order fines, including five to teenage children, after turning up at the gathering in Blue Gum Road at 6.30pm.
"On sighting police, the garage door was shut, and the occupants fled," police said in a statement.
"With the assistance of the Police Dog Unit, three people were detained nearby.
"Police spoke to the remaining occupants, and eight people, including five juveniles and three adults aged between 13 and 36, were issued infringements."
Children under the age of 12 are exempt from infringement notices, but older children are not.
Deputy Police Commissioner Michael Willing said at Sunday's NSW COVID-19 media update that police had issued fines to people who "thought they could gather at a residence in Jesmond".
The Jesmond gathering comes after two parties at Shortland and Blacksmiths on July 28 and July 30 were identified as seeding events for the virus in the Hunter.
Two Sydney women have been charged after allegedly attending the July parties having ignored fines issued in Newcastle and orders to return home. Both later tested positive for coronavirus.
Gatherings are banned under NSW's COVID-19 public health orders, and the government has increased fines and launched a stricter police crackdown on breaches in the face of rising case numbers.
The Hunter added nine new cases on Sunday, a result Premier Gladys Berejiklian described as "positive" and a "stabilisation".
Chief health officer Dr Kerry Chant said the "settling" of case numbers in the Hunter was pleasing, but she said health authorities were still concerned about potential coronavirus transmission in the Maitland area.
Hunter New England Health public health controller Dr David Durrheim said on Sunday that three out of five unlinked cases in the district were in the Maitland area.
"We know that there have been multiple, high-risk transmission sites in the greater Maitland area", including at the Guzman y Gomez restaurant at Green Hills shopping centre, Maitland Christian School and Sudania cafe in High Street," he said.
The Guzman y Gomez store is listed as an exposure site from 2.30pm to 8.30pm on August 7, 8 and 9 and from 5pm to 8.30pm on August 11.
Dr Durrheim said he was also concerned about Raymond Terrace, Williamtown and Medowie, where the level of viral detection in sewage was "as high as anywhere we've seen in NSW".
Three of the new Hunter cases were in Newcastle, three in Port Stephens, two in Maitland and one in Lake Macquarie. Eight of the cases are linked to known sources of infection and the other is under investigation.
The HNEH district has recorded 104 cases since August 5, including 24 on August 12 then five, 13 and nine on the following three days.
NSW reported 415 new cases in the 24 hours to 8pm on Saturday, the same day the government ordered the entire state into lockdown until midnight on August 21.
Dr Chant said another four people had died of COVID-19 in Sydney, including an unvaccinated woman in her 50s, a woman in her 70s who had only recently had her first dose, an unvaccinated man in his 80s, and a vaccinated woman who had chronic health issues.
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Police issued 31 infringement notices after breaking up a gathering of young people on the cliffs at Clovelly, in Sydney.
Dr Chant said the state's case numbers were "too high" and the community should stay at home for the next two weeks to bring them down.
"I am gravely concerned that the numbers will continue to escalate," she said.
Prime Minister Scott Morrison announced on Sunday morning that Australia had bought a million Pfizer does from Poland.
The first 530,000 doses, which are due to start arriving on Monday, will help vaccinate 20- to 39-year-olds in western Sydney.
Ms Berejiklian said NSW had reached 5 million administered vaccine doses and urged people to keep coming forward for jabs.
"Don't be too fussed about the type of vaccine you are offered," she said.
