A COVID-19 cluster has grown to at least seven cases with 2.5 million people in the region sent into a snap three-day lockdown on Monday afternoon.

Premier Annastacia Palaszczuk is expecting even more cases to be reported on Tuesday morning.

“We would expect to see more cases today, we’ve already got a few at the moment, so we would expect to see more,” she told Seven’s Sunrise program.

All seven cases are believed to be linked to a doctor at the Princess Alexandra Hospital on March 12.

They include the doctor’s sister, a Stafford man and his brother, and a Strathpine man who is friends with the Stafford man.

Two colleagues of the Strathpine man have also tested positive.

The doctor was not vaccinated when she worked one shift in the PA Hospital’s COVID-19 ward.

Palaszczuk said that was “unfortunate” as 7000 people had been fully vaccinated and 41,000 had received their first dose.

The premier blamed the outbreak on the surge in active cases in state hospitals in recent weeks.

Queensland Health is currently treating 73 active coronavirus cases.

“It’s been a huge increase in workload and the number of people who are positive with COVID that are currently in our hospitals so it’s a large number,” she said.

Palaszczuk said that Chief Health Officer Jeannette Young will order all state hospitals to mandate vaccination for anyone working directly with COVID-19 patients.

“That’s very good advice from Dr Young, and that strong advice we’ll get out to hospitals today,” she added.

Just two weeks ago, Health Minister Yvette D’Ath said that course of action would not be possible.

She said allowing only vaccinated health staff to treat with patients infected with coronavirus would cut the health workforce in half.

“That is not safe, that is not sensible, you can’t do that, no state’s doing that,” Ms D’Ath said on March 15.

The lockdown orders for anyone in the state who has been in the Greater Brisbane since March 20 is also causing problems outside the region.

The number of teachers self-isolating at home have left almost 30 Gold Coast, Scenic Rim and Darling Downs state and Catholic schools without enough adults to safely supervise students.

Those schools have now closed until next week.

“Due to the impact of the greater Brisbane lock down, some schools will be closed and unable to provide supervision to students,” the Department of Education said on Tuesday.

“These schools will have contacted parents and carers. Check the school closures website for a list of affected schools.”

Easter holiday plans are also in disarray as states and territories imposed strict border measures in response to the Brisbane cluster.

Western Australia has closed its border to the entire state of Queensland, while Tasmania, South Australia and Victoria have shut out Greater Brisbane travellers.

Anyone from Greater Brisbane must isolate and get tested upon entering the Northern Territory and the ACT.

In NSW, people who have been in the lockdown area since March 20 are now subject to the same stay-at-home restrictions as Greater Brisbane.