A man in his 50s was found dead in a Queensland hotel quarantine facility as the state reported four new locally acquired Covid-19 infections.
Queensland Police Deputy Commissioner Shane Chelepy revealed few details about the death, which was not being treated as suspicious.
"Tragically, overnight a male person in his 50s was found passed away in one of our quarantine hotels," he told reporters on Tuesday morning.
"I am not able to go into any more detail. What I will say is the matter is under investigation by police."
Authorities were also scrambling to contain two unrelated clusters that emerged on Tuesday, particularly an infected truck driver who was infectious in the community for more than a week.
The driver was staying at the Adalong Guesthouse in South Brisbane, which was under police guard early in the morning with reports of more than a dozen guests forced into isolation.
A man in his 30s from Eatons Hill in the city's north and his wife also tested positive, with chief health officer Jeanette Young saying the two clusters were so far unlinked.
The fourth case was a person who had exited hotel quarantine and was less of a threat to the community.
The top doctor said she was most concerned about the truck driver, who was infectious in the community since September 19, but insisted a "lockdown is not warranted at this stage".
"He stayed at three different places, two hotels in Spring Hill and a boarding house in Stevens Road in South Brisbane," Dr Young told reporters on Tuesday morning.
"We are working through with the managers of those three facilities as to who else was in those accommodation venues while he was there and organising quarantine for all of those people.
"We are continuing to work with him as to what other sites he has been at while infectious.
"But there have been a number that we have already been made aware of. That is why it is absolutely critical, please, anyone, particularly in Brisbane or that Moreton Bay region, particularly that western part of Brisbane, any symptoms at all, please come forward and get tested. That is absolutely critical."
Dr Young said the Eatons Hill man worked at an aviation training centre so it was possible he was exposed to the virus through a pilot.
"We are just working through that and I should get the whole genome sequencing later today to help," she said.
"As soon as he developed symptoms, got himself tested and confirmed positive, and has now been admitted to hospital."
The two unlinked clusters triggered health authorities to immediately reinstall the mask mandate outside of homes and whenever social distancing was impossible in Brisbane city and Moreton Bay.
Visits to aged care centres, hospitals, disability accommodation and detention centres was also paused in the two local government areas.