New South Wales has recorded 262 new community cases of Covid-19, with at least 43 of those cases infectious while in the community.
Of the new cases, 129 are linked to existing outbreaks and the source of infection for 133 cases is under investigation.
NSW Premier Gladys Berejiklian also confirmed five more residents died from the virus overnight, taking the state's current death toll in the latest outbreak to 21.
Four of the five were unvaccinated, and one had received just one AstraZeneca dose. Three were aged in their 60s, one person in their 70s, and one person in their 80s.
"Of course, we extend our deepest condolences to all of their loved ones at the tragic loss," the Berejiklian said.
"It's horrible that, during this time, families are losing their loved ones."
Health officials also expressed concern at the number of young people being admitted to intensive care.
NSW chief health officer Dr Kerry Chant said "we are seeing people in their teens, in their 20s and their 30s, as well as older individuals".
"I want to acknowledge that younger people have not had the opportunity to be vaccinated because of access to Pfizer," she said.
"I want to indicate that I'm aware of that. But my comments are that please now is the time to strongly consider getting vaccinated if you're over 18 and, for the elderly, who have not been vaccinated, again, I put out a plea to you – make an appointment."
There are also growing fears NSW's regional areas are now at risk after students at two Central Coast schools tested positive for the virus.
The Covid-positive students are believed to be siblings and three school campuses have now been closed for deep cleaning, prompting dozens of teachers and students to be put into isolation.
The developments have sparked fears the virus may have escaped Greater Sydney and could require tighter restrictions in the regions.
NSW health experts are convinced cases in the Newcastle/Hunter regions are connected to a get-together at a beach last Friday night.
Chant thanked those who attended the Blacksmiths Beach gathering for coming forward, and urged all residents to tell the truth.
"Can I just thank the people involved? Not that I want to see gatherings, but I also want people to tell us the truth," she said.
"If they've made a wrong judgement, if they've taken course of action that they regret, please tell us the truth because that will allow us to find out who was there and stop any chains of transmission."
She said she believed there may have been people from Greater Sydney who attended the gathering.
"That is in the best interests of everyone at this time for us to get to the bottom of it. And I think we need to work with individuals and I thank people for being open and honest with us, so we can track down any chains of transmission. I ask them to respect that as the principal objective at the moment."
Traces of Covid have been found in wastewater in Lake Macquarie, Port Stephens and Newcastle, despite no cases being officially recorded in those areas.
Victorians could know as early as this afternoon whether they will be sent into their sixth lockdown, with reports officials are considering a snap restrictions.
Six locally transmitted Covid-19 cases were confirmed this morning, with three of those infections unlinked, sending contact tracers scrambling.
Two more cases, which have not been included in today's numbers, were also announced during today's press conference. This brings the total new cases to eight.
The rise in cases sparked an urgent meeting between Victorian government officials and health authorities, with the Herald Sun reporting a snap three-day lockdown is being considered.
Sources told the publication consideration is being given to a lockdown starting at midnight but there is also the possibility of starting it earlier to avoid the risk of a "super spreader" event occurring from people gathering one last time before restrictions kick in.
No firm decision has been made but the Herald Sun reports any announcement will likely occur later today.
New exposure sites were added overnight in the state after health authorities detected a new mystery case in Truganina.
That positive case – a teacher at Al-Taqwa College – was announced yesterday just hours after the state recorded a doughnut day of zero new cases.
Victoria's health department said the mystery case had been out in the community while infectious and more exposure sites would be listed once they were identified.
The acquisition source of the teacher's infection was still under investigation and household contacts of the case were being urgently tested.
In Queensland, health authorities are dealing with the most significant Covid-19 outbreak it has faced since the beginning of the pandemic after another 16 community cases were recorded today, bringing the total number of cases in the Indooroopilly cluster to 79.
The state also recorded 11 overseas acquired cases – all from a ship anchored off Gladstone.
Deputy Premier Steven Miles said it was "very encouraging" that all of the new cases were linked and had been in isolation.
Authorities still don't know how the latest Queensland outbreak began. Genomic sequencing has linked the cases to two travellers who returned from overseas on June 29, but how the virus then went on to infect a high school student remains a mystery.
Chief health officer Jeannette Young said it's possible it "could have been someone who got infected at the airport or in hotel quarantine or in the hospital or in the community" who then passed it on to the school student themselves or through an intermediary.
"So, yes, it's absolutely possible we'll never find the missing link," Young said.
Miles said yesterday that the continued increase in case numbers made the situation "our biggest outbreak since the first wave last year".
Queensland's authorities have said they're becoming increasingly hopeful the lockdown will end on Sunday as planned – but either way, the state won't be returning to normal.
"If we are able to lift those stay-at-home restrictions on Sunday, of course we will be going and continuing with other restrictions," Young said. "But that's if we can lift it on Sunday. We've still got a while to go."
Young warned residents yesterday that the government would be prepared to again extend the lockdown if it was necessary.
"I look at other states and how long it's taken before they could lift their restrictions. If we don't do something really, really, really special in Queensland, we'll be extending the lockdown."
The Queensland lockdown applies to 11 local government areas (LGAs) in the southeast and affect approximately 3.8 million residents out of the state's population of 5.1 million.
The LGAs are: Brisbane City, Moreton Bay Regional Council, Gold Coast, Ipswich, Lockyer Valley Regional Council, Logan City, Noosa Shire Council, Redland City, Scenic Rim Regional Council, Somerset Regional Council and Sunshine Coast Regional Council.
People can only leave home for four reasons: to obtain essential goods like groceries and medications – but only within 10km of their homes, for essential work or childcare, medical care and exercise.
Brisbane residents have been urged to monitor the Queensland Health website.
The NZ Ministry of Health is urging people who have recently returned from Queensland to check whether they visited any of the state's locations of interest.
Director general of health Dr Ashley Bloomfield said anyone who had visited the relevant locations should immediately isolate and call Healthline on 0800 358 5453.