The woman, from Bli Bli on the Sunshine Coast, was confirmed with the more infectious variant overnight as authorities sought to contact another 169 Queensland miners put at risk by a quarantine breach that already infected another worker transiting through Brisbane.

With at-risk miners having flown all over the country in recent days, an infected flight attendant having crewed flights into Brisbane and the Gold Coast, school holidays in two states and Sydney and surrounds still being in lockdown, Queensland faces an anxious wait to determine whether other people infected with the more contagious Delta variant have been in the community. Premier Annastacia Palaszczuk says the state is “on the verge” of another costly lockdown.

Chief Health Officer Jeannette Young said that although the Bli Bli woman had visited shops and service stations while infectious, she had done the right thing by immediately responding to a Queensland Health text message and cancelling the family trip.

Her family are feared likely to have contracted COVID-19 but Young said she was thankful they could be isolated relatively quickly and had only been in the community for a day.

“What I’m more concerned about is the unknown,” Young said, referring to the other miners and passengers and staff on various flights.

“We’ve got enormous risks throughout our state.”

As Queensland Health continues to contact and test hundreds of people deemed at risk, millions of people in the south-east will be ordered to take precautions out of fear the Delta variant may already be circulating.

From 1am Tuesday, masks will be mandatory in public, except while exercising, in the Noosa, Sunshine Coast, Ipswich, Logan, Redlands, Moreton, Brisbane, Gold Coast, Scenic Rim, Lockyer Valley and Somerset council areas.

Masks will be required for at least two weeks and the area will be expanded if required.

Crowd limits will also be reduced, interstate travel restrictions will be enforced and reviewed, and compliance with check-in apps will be crucial.

Palaszczuk today acknowledged south-east Queensland was “on the verge” of lockdown if there was uncontrolled community spread of COVID-19.

“The next 24 to 48 hours are going to be very crucial in Queensland,” Palaszczuk said.

Young said she was hopeful Queensland could avoid another lockdown, the first since Brisbane’s three-day lockdown in January when the UK strain, now known as the Alpha variant, leaked out of quarantine and a hospital.

“We may, of course we may, but we have got so much more that we can do now compared to January,” she said, referring to the improved check-in apps and contact tracing procedures, as well as the unexpectedly high take-up of masks in January.

“We’ve been doing this for 18 months now and people, and businesses, know what they’re doing.”

The threat posed by the Delta variant again overshadowed an outbreak of the Alpha variant and another case confirmed at the Portuguese restaurant. It was sparked by a flight attendant only testing positive after she had left hotel quarantine.

Overnight, a third case of COVID-19 was also confirmed in Queensland, detected in hotel quarantine.

Palaszczuk said she would ask National Cabinet to again lower the cap on international arrivals and finally move ahead with regional quarantine facilities to replace city-based hotels.

“We have seen leaks out of hotels in a large number of states, it is not unique to Queensland,” Palaszczuk said.

“It is a national issue.”

Young acknowledged the miner who inadvertently sparked the latest crisis, having caught the Delta variant during a brief stopover in Brisbane hotel quarantine, had been housed alongside returning international travellers at the airport Novotel.

“We don’t usually but we’ve been under a lot of pressure in our hotels,” Young said.

“It’s just the pressure that’s led to this having to happen.”

The Delta variant had already spread within the Novotel, prompting Queensland Health to alert all former guests, which led to the man being tested at the Northern Territory as hundreds of workmates continued to fly-in and fly-out.

Prime Minister Scott Morrison has proposed a Defence site near Brisbane Airport being used to house 1,000 travellers, however it would not replace hotel quarantine and the Palaszczuk Government also wants a Toowoomba Wellcamp airport proposal to go ahead.

Governments have yet to agree to open up international travel, and are struggling to fast-track the vaccination rollout to ensure Australians at least have some protection.

Brisbane hosted the second State of Origin game on Sunday night, bringing some 56,000 fans and staff to Suncorp Stadium for several hours. Masks were a late requirement for getting to and from seats, but Young said check-in apps worked and COVIDSafe plans were in place so she was not concerned about the potential for an outbreak linked to the event.