A Sydney resident travelled on a flight from Sydney to Griffith on December 21 subsequently returned a positive test result for COVID-19 on December 24.

MLHD director of Public Health, Tracey Oakman, said the person flew before they knew they were a close contact of a case and did nothing wrong.

"The flight left Sydney at 2.10pm and arrived in Griffith at 4.20pm," she said.

"It stopped briefly at Narrandera however no passengers left the plane at that point.

"Twenty-eight passengers and one flight attendant, and members of one household that the person visited after arriving in Griffith, have been identified as close contacts."

Earlier, the MLHD said after arriving in Griffith the person was contacted by NSW Health to advise that they had been identified as a close contact at a Sydney venue.

They then returned to Sydney by car where they were tested and returned a positive result.

Ms Oakman said all close contacts must get tested and self-isolate immediately, and remain in isolation for 14 days since exposure, even if they receive a negative test result.

IN OTHER NEWS:

People sharing a house with the close contact will also need to self-isolate until the close contact receives their initial test result.

"We thank all of the people identified as close contacts for following the health advice," she said.

"No other contacts have been identified in the region to date, and all tests completed so far have come back negative.

"Anyone who develops even the mildest of symptoms such as headache, fatigue, cough, sore throat or runny nose, is urged to come forward immediately for testing, then isolate until they receive a negative result."

NSW Health reminds people that calls from their contact tracing team may come up as 'No Caller ID' and encourages people to answer so they can receive the appropriate health advice and any assistance they may need.

Testing continues in Griffith, and across the region, every day over the Christmas and New Year period.

Griffith testing clinics:

If you need testing after 5.00pm, go to Griffith Base Hospital. Please call the Murrumbidgee COVID-19 Hotline on 1800 831 099 (between 8am to 6pm or call the hospital directly on 6969 5555 after 6pm).