Hunter public health controller Dr David Durrheim says people mixing in the community despite showing COVID-19 symptoms are contributing to record case numbers in the region.
The Hunter reported 45 cases on Wednesday, the most since the pandemic began last year.
The cases were spread across 28 suburbs and included 29 who were infectious in the communty.
Dr Durrheim said one woman had been active in the community for five days while displaying symptoms before testing positive.
"The really concerning issue is the large proportion of cases that actually were infectious in the community with COVID-19," he said.
"A number of those cases were infectious with symptoms for a number of days before they got tested. It gives the virus an opportunity to accelerate ahead of us."
The daily case tally was 15 higher than the previous record during the latest outbreak and 11 more than last year's record.
Only last month, Deputy Premier John Barilaro hailed the Hunter as "the only jurisdiction possibly in the world that can get back to zero", but case numbers have headed north ever since.
Of the cases announced on Wednesday, 20 were in Newcastle local government area, 19 in Lake Macquarie, three in Maitland, two in Cessnock and one in Port Stephens.
The list of exposure sites is growing rapidly each day and now includes dozens of shops, supermarkets, hardware stores, medical centres and Newcastle Airport.
Meanwhile, the government is weighing up whether to adopt a staged approach to reopening regional travel once the state hits vaccination targets next month.
The vaccination rollout in parts of the Hunter and in other regional areas is several weeks behind the state average, raising concerns some communities will be vulnerable to Sydney visitors and their unvaccinated children.
"We're taking feedback, and the Deputy Premier and I have been engaging with local MPs and mayors about this," Parliamentary Secretary for the Hunter Taylor Martin said on Wednesday.
Hunter Business chief executive officer Bob Hawes said business was keen to reopen, but it would be counterproductive to open some areas too soon and risk a serious outbreak which could lock them down again.
Restarting regional travel also raises broader ethical questions about exposing communities to the virus if supply issues have prevented them from being vaccinated.
NSW recorded 1035 cases on Wednesday.
Five more people died with COVID-19, including two who were not vaccinated, two who had received one dose and a woman in her 80s with underlying health conditions who had received two doses.
Eleven of the 342 active cases in the Hunter are being cared for in hospital but none are in intensive care.
More than 800 close contacts are in isolation.
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