Queensland Premier Annastacia Palaszczuk told reporters that mask-wearing is now compulsory for people in the rest of the state and home gatherings will be limited to 30 people.
Two of them are under investigation.
Premier Palaszczuk said no decision has been made about extending the lockdown beyond Thursday.
So, we have a cluster linked, of course, to that PA doctor.
One known case lives on the Gold Coast and others have visited Toowoomba, Gladstone, Hervey Bay and Gin Gin while infectious.
Chief Health Officer Jeannette Young has left open the door to expand the lockdown to other regions.
Eight new COVID-19 cases were detected in the community as of Tuesday, and health authorities now believe the 15 locally acquired cases of recent weeks are related to two "distinct" clusters, both of which have originated from the Princess Alexandra Hospital.
The nurse's sister has also been infected with the virus.More news: World Health Organization chief says all possible COVID origins 'need further study'
"So far the fact that we have these cases that are linked is good news".
"The next two days are critical for our contact tracers to get on top of this", 'she said.
"But we've had a lot of people now out in the community while infectious".
Ms Palaszczuk said those who had tested positive had been out in the community, making the job of contract-tracing a huge one.
All residents have been vaccinated.
Queensland has also mandated that healthcare workers must have received their first vaccine dose to be able to treat COVID-19 patients.
"It depends on what we see [in terms of cases] over the next 24 to 48 hours", the Premier said.More news: Biden says Justice Department looking into Georgia election law
More than 41,000 frontline workers have received their first jab already, but only about 7000 are fully vaccinated.
"It's too early to decide what may or may not happen", Dr Young said.
She is expected to hold a media conference at 9am.
Otherwise, we've got this-see you on the flipside.
Australia's Queensland state warned on Tuesday that more cases of COVID-19 were expected to emerge as authorities scrambled to contain an outbreak linked to the virulent United Kingdom variant, throwing Easter travel plans into disarray.
She says there are now two distinct clusters of the United Kingdom variant of Covid-19 in Greater Brisbane, which has been locked down to stem the spread. "It worked effectively when we did it last time".
"I know this is a really big call, I know it's very tough - we've got Easter coming up, we've got school holidays coming up", Ms Palaszczuk said.
Eight people with overseas acquired cases of COVID-19 are now being treated at Sunshine Coast University Hospital, Queensland Health has confirmed.More news: Australia's Queensland state coronavirus cluster grows to three