A crew member from a coal ship that is berthed in the Port of Newcastle is being treated in John Hunter Hospital for COVID-19.
The ship, Anacapa Light, arrived from Brisbane on Thursday.
Nursing staff swabbed the 14 crew members that had recently boarded the ship from India.
One of the crew, a man in his 20s, tested positive for COVID-19 and is receiving medical care and further tests at John Hunter Hospital.
Cargo ships are usually brought to the wharf by a Newcastle-based harbour pilot and the NSW Port Authority confirmed this was the case with the Anacapa Light.
It is understood the pilot wore protective equipment and will not be required to quarantine because he was not considered "a close contact".
A Hunter New England Health spokeswoman said the crew member appeared well.
"Infection control measures are in place and the hospital remains safe for patients, staff and visitors," she said.
"All other crew members are considered close contacts and will remain on board for quarantine and monitoring. Ongoing management of these crew will be determined. Further investigations are underway.
"It is important to note that the only people at risk are the immediate crew who have not left the ship, and there is no COVID-19 risk to the people of Newcastle.
NSW Chief health officer Kerry Chant said it was initially thought the man had an old infection, but further testing is underway because the results were inconclusive
"I should stress no-one is at risk in the community from this," Dr Chant said on Friday.
"We need to be thorough in completing that additional testing."
A Port of Newcastle spokeswoman said the port continued to take seriously government advice about measures to prevent COVID-19.
"We continue to work with all agencies involved in the movement of vessels, crew and cargo through the port, including vessel operators, Australian Border Force, NSW Health, NSW Police, Department of Agriculture and Port Authority of New South Wales," she said.
"Our measures and actions are informed by and aligned with the official advice and requirements.
The ship is due to leave port on Saturday night bound for Indonesia.
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