NSW Health is undertaking an extensive investigation into the source of a new COVID-19 case, including the possibility of transmission within a hotel quarantine facility.

The case, reported today, is a returned overseas traveller who tested positive to COVID-19 after being released from hotel quarantine at the Sofitel Wentworth.

Comprehensive testing is underway to assist NSW Health understand the timing and nature of the case's infection, including whether their infection is a known variant of concern.

Several returned overseas travellers in the same quarantine hotel returned positive COVID-19 results while the case reported today was undertaking quarantine. NSW Health is investigating any potential links between these cases and today's case.

All returned travellers who stayed on the same floor in the Sofitel Wentworth during this time are being contacted by NSW Health contact tracers and requested to be tested if they have not already been tested as part of the day-16 testing program.

All staff working in NSW quarantine hotels undertake a daily rapid saliva test as part of COVID-19 surveillance testing.

The person, from the Wollongong area, arrived from South America on January 19 and commenced hotel quarantine. They returned two negative tests during their quarantine period. These tests were taken on day-2 (21 January) and day- 12 (31 January), before the person finished their hotel quarantine period on Tuesday 2 February.

NSW Health contact tracers contacted the person late on Thursday February 4 as part of the enhanced day-16 follow-up, introduced last week.

They did not have any symptoms but agreed to undertake testing the next day, doing so on the afternoon of Friday 5 February. The test was returned as a positive on the night of Saturday 6 February. The person was contacted, interviewed by NSW Health, isolated, and re-tested, with those results re-confirming a positive detection on Sunday 7 February.

Ten close contacts of the case were also identified and directed to self-isolate. Seven of those have already returned negative tests.

The person visited a number of venues in Wollongong and surrounding areas, as well as a café in Brighton Le Sands in south-eastern Sydney, before they were notified of the positive result from their day-16 test.

A complete list of venues of concern, and the related health advice, is available on NSW Government - Latest news and updates.

​There are more than 350 COVID-19 testing locations across NSW, many of which are open seven days a week. To find your nearest clinic visit COVID-19 clinics or contact your GP.

NSW Health last week introduced additional testing of people who are discharged from hotel quarantine after 14 days. When discharged from hotel quarantine, these returned travellers now receive a fact sheet explaining the need for this test.

They are subsequently called by NSW Health's contact tracing team on day 16 and asked if they have any symptoms, and regardless of whether they have symptoms, are asked to get tested that day or the next day. If they have no symptoms they are not required to isolate while they await the results of this test.

No quarantine system is without risks. Day 16 testing was introduced following the identification of people who had developed COVID-19 infection after leaving quarantine in other jurisdictions.

Such testing may pick up infection that has developed from exposure during the quarantine period or in those rare instances where cases have long incubation periods.