"This has become our biggest outbreak since the first wave last year," he told reporters on Wednesday.
Four cases are linked to the Ironside State School, two are linked to Indooroopilly State High School, one is linked to Brisbane Boys Grammar and nine cases are close contacts or family members.
Another new Delta case in Cairns is not genomically linked to Brisbane cluster.
The case is a reef pilot who is fully vaccinated with Pfizer and he's believed to have been infected by a crew member on a ship.
Almost 10,000 people are in home or hotel quarantine, and two new cases were not in the community for any point of their infectious period.
QLD records 16 new local cases
Chief Health Health Officer Jeannette Young said there's still hope the lockdown could end at 4pm on Sunday.
The aim of the lockdown isn't to eradicate the cluster, she said, but keep the number of people infectious in the community down.
"It doesn't matter (if) we've had those cases because they're in quarantine, so it won't stop us lifting the restrictions on Sunday," she said.
"So please, everyone just think of what you can do in the next few days so we can lift this and we can beat all their predictions about how long it takes to get such a large cluster under control."
Police issued 48 penalty infringement notices on Tuesday, including 34 to people for breaching lockdown without a valid reason.
Mr Miles urged people to stay home unless they absolutely need to do essential shopping or get health care.
"You can't go out because you need milk, but stop to look at EB Games or JB Hi-Fi," he said.
"So the requirements are there, the police are checking people for the first time those RBT style interceptions. We just urge everyone to really, just for a few more days we hope, do the right thing.
"Five more days, do the right thing, and then next week you can buy all the sun lounges you think you need."
Dr Young asked people to even delay online and "click and collect" shopping for non-essential items until lockdown lifts.
"I'm a great online shopper, could you think about whether you need to do online shopping this week," she said.
Queensland's Ekka public holiday set for next Wednesday will also be rescheduled.
Health Minister Yvette D'Ath said she hopes to receive 150,000 extra AstraZeneca vaccine doses from the Commonwealth next week.
"If (federal Health Minister" Greg Hunt's says they've got 150,000 now, which I have no doubt they do, of AstraZeneca then it should be on trucks today," she said.
Ms D'Ath also said the government was also trying to work out what was causing vaccine hesitancy in Queensland.
"We do a lot of consumer advocacy and reach out to find out why it is that we, you know, have a vaccine hesitancy or why we're not coming forward," she said.
"We need to break down the data as to whether it's AstraZeneca or Pfizer."
Until recently, the state government had warned people under 40 not to get AstraZeneca due to the extremely small risk of a rare blood clotting disorder, which is treatable.
Earlier this week, Dr Young changed her advice and said people who think they are at risk should talk to their GPs about getting AstraZeneca.