UPDATE:
Hunter New England have clarified the Sydney person was not a worker on the construction site, rather a Costco employee from Sydney who worked in the membership office.
Lake Macquarie MP Greg Piper says Costco has announced it is delaying its opening which was due to be on August 26.
300 people are now isolating as close contacts of the person.
EARLIER:
A Sydney construction worker who worked on the construction site of Costco at Boolaroo has tested positive to COVID-19.
Hunter New England Health have issued an alert regarding the work on Friday asking anyone who worked on the site since Monday 16 August get tested and isolate immediately.
Another area of concern is the Costco petrol station and membership office also at Boolaroo between Monday 16 August and Thursday 19 August. Anyone who was at either venue at the specified dates and times is considered a casual contact and must get tested and isolate until a negative result is received.
Over 300 contacts to date have been identified and are being contacted for testing and isolation requirements.
Public Health Physician Dr David Durrheim says he wants employers to think about their workforces.
"We really at this stage think that people, employers need to think very carefully about the origins of their workforce. We cannot have more and more cases being imported into the Hunter from Sydney by employers," Dr Durrheim said.