Queensland has declared all of Greater Sydney a COVID-19 hotspot and will close its borders to the region from 1am on Saturday 1 August.
As such, people who have been to Sydney within the last 14 days will not be allowed to enter the Sunshine State.
Queensland residents will be allowed to return, but they will have to isolate in a hotel for 14 days at their own expense.
The move will see 31 new local government areas (LGAs) added to the list of three existing LGA hotspots previously delcared by the Queensland Government because of new outbreaks in the NSW capital.
"It is going to cause an inconvenience to families...but it is important," says Queensland Premier Annastacia Palaszczuk.
"We must protect Queenslanders, and your safety comes first. We are in extraordinary times at the moment and we have to do everything we can."
BREAKING: Queensland will close its borders to all of Greater Sydney. From 1am Saturday, more hotspots will be declared and no one from Sydney will be allowed into Queensland. #COVID19au pic.twitter.com/044iZeTZ1gAnnastacia Palaszczuk (@AnnastaciaMP) July 29, 2020
The announcement follows news that two new confirmed cases of COVID-19 in Queensland have been out in the community for eight days whilst unwell, forcing Queensland Health to close some shopping malls, restaurants and a church.
The two cases, both 19-year-old women who live in the Logan and Acacia Ridge areas, returned from Melbourne on 21 July and did not isolate at home for the requisite 14 day period.
As such, Queensland Health is working to identify the numerous close contacts of the two women, will close a number of businesses and a church for deep cleaning for 48 hours, and will place aged care facilities in the Metro South region into lockdown.
A criminal investigation into how the women managed to travel to Victoria and return to Queensland without going into quarantine will also be undertaken.
One of the women is employed as a cleaner at the Parklands Christian College in Logan, which has since been closed for deep cleaning.
Meanwhile, Priority Health Medical Centre has relayed information from Orion Shopping Centre, where one of the women attended the Peak Thai restaurant recently.
"We have been advised [By QLD Health] that the person was a patron who visited Peak Thai on Sunday 26th July 2020, in the evening," the shopping centre reportedly told the medical centre.
Both women are currently being cared for at the Princess Alexandra Hospital in Brisbane.
Premier Palaszczuk says she is "furious" about the conduct of the pair that will cause significant inconvenience to those in the local community.
"I am absolutely furious that this has happened, that these two people have gone to Victoria and come back and have given to authorities misleading information," says Palaszczuk.
"There will be a thorough police investigation here, and now we have to act as a community."
According to Queensland Deputy Premier and Minister for Health Steven Miles the pair travelled together to Melbourne and returned to Brisbane on 21 July on a flight via Sydney.
Close contacts on flights VA863 and VA977 are being contacted currently.
Chief Health Officer Dr Jeannette Young says she is disappointed by the behaviour of the two women which has put lives at risk in Queensland.
"It is very disappointing that this has occurred" says Dr Young.
"As a result of that, a lot of people are going to be inconvenienced and I do apologise to those people for what is now going to have to occur.
"We know if we act really fast we can stop this spreading further and cause even more inconvenience to a lot of people."
Queensland Deputy Police Commissioner Steve Gollschewski says a criminal investigation will seek to uncover how the pair managed to cross into Queensland from Melbourne without having to go into quarantine.
"Our investigations are around the truth so we want to work out what actually happened here, in terms of what individuals may have done but also how the system has operated and see whether there are things we need to consider," says Gollschewski.
"What this highlights is why it is so important that everybody who engages with that does the right thing.
"There is so much community transmission [in Victoria], you're putting everyone at risk if you don't declare that and certainly, there are systems in place to help people get through that."
Dr Young has urged anyone who displays symptoms in the Logan, Acacia Ridge and Springfield Lakes regions to get tested immediately and self-isolate.
"There will be additional fever clinics put in place but please, see your own GP, go to one of the fever clinics that are there and get yourself tested as soon as possible," says Dr Young.
"If you are unwell, stay at home and isolate yourself. That is the way we can all work together to stop this further spreading."
Updated at 11:19am AEST on 29 July.