Brisbane's COVID-19 outbreak has swollen to 47 cases with the state's chief health office warning the state is on the verge of a "large outbreak".
The 16 new cases announced on Tuesday are all linked to the west Brisbane Delta cluster, which has grown from one to 47 cases in four days.
A 17th case was recorded in North Queensland, with contact tracing locations in Cairns, Trinity Beach and Yorkey's Knob. A Qantas flight from Brisbane to Cairns on Thursday morning has also been listed.
The circumstances are currently being investigated and Queensland Health advised more information would be released on Wednesday.
"Tests are currently being performed to determine whether there is any infection risk to the community," it said in a statement.
Chief Health Officer Jeannette Young says the 34,718 tests conducted overnight is encouraging, but she still wants 40,000 per day.
She's urging people in the southeast to stay home until a hard lockdown ends on Sunday.
"Please don't move the virus," Dr Young told reporters on Tuesday.
"So wherever you are in those 11 LGAs, if you can at all, just stay put so that that virus then doesn't move, because we know that there are people out there who could have been infected, who have no symptoms.
"So the best way to deal with someone who has no symptoms is that they just stay at home. That's why lockdowns work, because we know that the virus can burn out. So please just stay at home."
Deputy Police Commissioner Steve Gollschewski said 70 infringement notices were issued and 21 people were arrested overnight.
He said police will move to install RBT-style roadblocks to enforce the hard lockdown.
"We'll start RBT-type stops at intersections to check if people are allowed out for a valid reason," Mr Gollschewski said.
"There is nothing to fear if people are doing the right thing."
Dr Young has previously advised younger adults not to get the AstraZeneca vaccine, but she admits that's set to change.
She said under 60s who feel they're at risk should speak to their GPs about that vaccine.
The Commonwealth is sending another 150,000 doses of AstraZeneca to Queensland after declaring the southeast as a hotspot.
Dr Young said her advice that 18-year-olds shouldn't get AstraZeneca will change if the cluster grows any more.
"The ATAGI advice says when you reach a large outbreak - which I think we're on the verge of, I hope it doesn't become any larger, but I suspect it will - then that is the time," she said.
One new case is linked to Indooroopilly State High School, four are linked to Brisbane Grammar School, two are linked to Brisbane Girls Grammar, three are linked to Ironside State School, five are household or family contacts and one is a neighbour.
Nine of the 16 new cases are children and some have been infectious in the community for six days.
Dr Young said 7995 people are in home or hotel quarantine, including more than 400 health workers.
Some surgeries and outpatient services will be delayed, the chief health officer said, because of staff shortages.
"No Queenslander will be denied any care because the health workers they need are in quarantine, we'll work through that," Dr Young said.
Most of the quarantined health workers have been vaccinated, she said, but there's a risk of them passing on the virus to their patients.
Dr Young said the link between the original family that was infected and two overseas acquired cases who were treated at the Gold and Sunshine Coast hospitals is still unclear.
"There's still missing cases between them, absolutely, but possibly not a large number, but we know even one case can lead to another outbreak," she said.
Australian Associated Press