Hunter New England Health has listed the Belmont vaccination hub as a COVID-19 exposure site.
The health service said a confirmed case was unknowingly infectious when they attended the hub on Friday from 11.45am to 12.45pm.
Anyone who was at the vaccination centre during this time must get a test and isolate until they receive a negative result.
They must also seek a second test on Wednesday.
HNEH is also contacting close contacts from the exposure.
NSW Health also listed new exposure sites at Port Stephens Bunnings at Taylors Beach on August 27 and September 1, Cellarbrations Bottle Shop at Shoal Bay on August 30 and September 1, and Thornton Subway on September 3.
The Newcastle Herald understands a Centennial Coal employee listed on Friday as a positive case has since returned a negative test result.
The employee worked at the Mandalong mine near Morisset last week.
On Sunday, HNEH removed one case attributed on Friday to New Lambton and another allocated to Armidale.
The Herald is seeking official confirmation that the New Lambton case was the mineworker.
Hunter New England recorded 12 new cases on Sunday.
