Queensland has announced Chief Health Officer Jeannette Young's successor as the state records two new virus cases while working to control another outbreak.

One of the new cases, a three-year-old girl, is linked to the aviation cluster in the state's southeast and has been in quarantine during her entire infectious period.

The second is a Queensland resident given an exemption to return from Melbourne, who acquired the virus interstate and was notified as a positive case while on a flight on Monday.

Health authorities met the 19-year-old at the airport and transferred her directly to hospital. All other passengers on the flight were required to enter hotel quarantine.

Premier Annastacia Palaszczuk said neither case posed significant risk of infection to the community.

The latest figures come as Chief Health Officer Jeannette Young prepares to hand the reins of the state's pandemic response to infectious disease doctor Krispin Hajkowicz.

Dr Hajkowicz is currently the Royal Brisbane and Women's Hospital Director of Infectious Diseases, and will take over from Dr Young when she steps down on November 1.

Dr Young said her replacement had been heavily involved in the state's response to the pandemic and was "the perfect person" to take on the role.

""He has been the lead in the treatment and management of COVID cases and it is no accident that Queensland has only had seven deaths out of our 2048 cases so far," she said on Tuesday.

The new chief health officer will step in during a challenging period for Queensland, with questions being raised about state hospitals' preparedness for COVID-10 outbreaks when borders re-open, and pressure to lift the vaccination rate.

"(Dr Hajkowicz) has been keeping right on top of the new treatments that are available going forward and that is what we will need," Dr Young said.

"The virus will come in, no matter what we do."

Dr Hajkowicz said he was "thrilled and honoured" to be the state's next chief health officer and had been working on his hospital's "frontline" of COVID-19 response for the past 18 months.

"'I've been involved in pandemics for a long time now, this will be my fourth big pandemic," he said.

As the state moves away from stopping the virus to treating more cases in hospital, Dr Hajkowicz said it was "the right time" for someone with a clinical background to take the top job.

Dr Young is to become Governor of Queensland.

Meanwhile, the origin of a mystery case reported on Monday is yet to be confirmed as authorities continue to identify contacts and exposure sites.

Genome sequencing has confirmed the woman in her 50s has the Delta variant, but it has not yet been linked to any known cases in the state.