The positive case, which has not yet been confirmed as the Delta variant, was discovered on Thursday, leading to a frenzied search for 160 to 200 contacts of the 31-year-old New South Wales man.

Many of these contacts have been identified and tested, and no positive cases have been detected.

They include hotel and health workers and police who are now in quarantine but continue to be tested daily, the taxi driver who drove the man to the airport, and also people who were on the same floor as the infected man in hotel quarantine.

READ MORE: NSW residents fleeing COVID put pressure on hotel quarantine

It also included up to 100 people who travelled with him on the same flight from Melbourne to Launceston on Monday, August 2, of which 20 remain unaccounted for on Friday afternoon.

Public Health director Mark Veitch said passengers who landed in Launceston on Monday, onboard Virgin flight VA1364, have been sent SMS messages and email.

"There was a small number of people in that group, about 20, who we were embarking upon further calls this morning," Dr Veitch said.

"Sometimes it is difficult to catch up with people on the flights, either the wrong number or out of contact range, so we are working with other colleagues and agencies so we can see where those remaining people are."

"We are concerned that people on that flight back on Monday were not part of the quarantine process. That is why we are actively getting in contact with those people to make sure none of them are cases," he said.

"My message is, if you were on flight VA1364 from Melbourne to Launceston on Monday, and haven't yet been contacted directly by phone, by Public Health, please call the Public Health Hotline on 1800 671 738."

As contact tracing continues authorities have scaled up the testing clinics to ensure any possible cases of Covid-19 are detected quickly, and are reminding people to get vaccinated.

In the last 48 hours up until Friday morning, there have been more than 3400 tests carried out across the state, including 1643 tests in the past 24 hours.

A further 1189 people had made appointments for testing by noon on Friday, but hundreds of test appointments are still available.

Appointments for COVID vaccinations in state and national clinics also remain available, and pharmacy vaccinations are set to begin on August 15 with 11 of the 26 pharmacies planned to begin the rollout.

This includes Legana, but more than 100 pharmacies also put up their hands for the rollout in the future.

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