Queensland has recorded no further cases of community transmissions as authorities try to figure out how a flight attendant contracted COVID-19 while in hotel quarantine.
Genomic sequencing results show the woman in her 30s has the less infectious Alpha variant that has been linked to a case in the same hotel.
The two cases arrived on different flights and were staying on different floors, Chief Health Officer Jeannette Young said on Monday.
"She acquired her infection from another cabin crew member who was in quarantine at the Four Points hotel," she said.
"I'm pretty confident that (the source of infection) won't have been through staff, as we know that our staff get tested every single shift."
Previous cases of virus transmission within hotels have involved people staying on the same floor, Australia's Chief Health Officer Paul Kelly said on Monday.
"It appears that the transmission was from a quite high floor to a relatively low floor (which) would be a world first, so I think the more logical explanation would be it's a staffing matter," he said.
The flight attendant was a passenger on board an Emirates flight that landed in Brisbane on June 5.
She undertook hotel quarantine in preparation for starting work with another airline.
Three tests returned negative results during her isolation period, and the process is effective in in picking up "99 per cent of cases", Dr Young said.
However the positive result wasn't determined until Saturday when the woman took a routine test as part of the standard practice for cabin crew.
She spent time at a direct factory outlet at the airport, in Brisbane's CBD and in the suburb of Ellen Grove between being released from quarantine and confirmation of the case.
Cotton-On at the DFO has been identified as a venue of particular concern.
"It's important that anyone who went to the DFO between 4pm and 4:30pm, on Saturday comes forward...so that we can work with them and what risks they may have," Dr Young said.
The news comes with fresh hope there won't be any further restrictions to Queensland's border ahead of school holidays.
Queensland Police Acting Chief Superintendent Rhys Wildman said he was "very hopeful" the borders will stay open as Queensland, New South Wales and Victoria count down to the break beginning on June 26.
"The Gold Coast is open for business, the residents and actually the businesses here, the hotels, are very much looking forward to the school holidays," he told Channel Nine on Monday.
Queensland is also preparing to ease more internal restrictions on Friday.
Capacity at indoor venues is set to increase and limits on gatherings removed.
Health Minister Yvette D'Ath said the changes were possible because of the state's check-in app and confirmed more venues will have to use the system.
"Places like food courts, open houses, hairdressers, casinos, theme parks and caravan parks will be required to use the app," she said on Sunday.
The state recorded five new cases in hotel quarantine, bringing the active total to 32.
Australian Associated Press