Queensland has recorded a third new local case of COVID-19 in a man who was out in the Sunshine Coast community while infectious.
Queensland Health said in a statement on Sunday night that the case was a miner who had returned from working in the Northern Territory.
The Territory is currently battling an outbreak at the Granites mine in the Tanami desert.
The man transited through Brisbane Airport on Friday and travelled to the Sunshine Coast. He was infectious in the community for a day.
Hundreds of potentially exposed fly-in, fly-out mine workers are currently isolating in Queensland and Western Australia.
It comes after the state recorded two new local cases of COVID-19, a couple active in the Brisbane community for several days.
The two infections are believed to be linked to the existing Brisbane cluster that began in a Portuguese restaurant and not in Sydney.
While the couple didn't attend the eatery, Chief Health Officer Jeannette Young says one of the cases is a friend of a patron.
That person did not develop symptoms but got tested because they were working at Brisbane Airport's Direct Factory Outlet, which was listed by Queensland Health as an exposure site.
"We are going to deem them as infectious in the community from the 20th of June," Dr Young told reporters on Sunday.
"They've been to a lot of sites throughout the community which we'll put up on our website, several gyms (and) several shopping centres."
The person's partner, who lives in the same home, also tested positive.
More than 20 new exposure sites were listed later on Sunday.
If Brisbane's two initial new cases are definitively linked to the city's existing cluster, which involves the Alpha variant of the disease, they would take the outbreak to nine known cases.
Meanwhile, authorities are working to contact passengers aboard Virgin flights with a staff member who has since tested positive for the virus.
Five Virgin Australia flights on Friday and Saturday took passengers either to or from Brisbane, Melbourne, Sydney and the Gold Coast.
"Fortunately the flights were fairly empty because of all of the restrictions with Sydney," Dr Young said.
Millions of people in NSW have endured the first day of a fortnight-long lockdown with residents of Greater Sydney, the Blue Mountains, Central Coast and Wollongong ordered to stay at home until at least July 9.
The lockdown came after the number of COVID-19 cases in the harbour city swelled by 12 to 110 on Sunday.
Dr Young said there is "a lot happening" in Queensland and urged anybody with symptoms to get tested as soon as possible.
Queensland will also revert to previous venue density requirements and a cap of 100 guests at private homes for the two-week duration of NSW's current restrictions.