NSW has reported 291 new locally acquired cases of Covid-19 today - the highest daily tally of the current outbreak.

Of those cases, 48 were infectious in the community, and the isolation status of 104 remains under investigation.

Officials also reported another Covid-19 death - a woman in her 60s from south-west Sydney who died at Liverpool Hospital. The number of Covid-related deaths during the current outbreak is now 22.

There are 304 NSW Covid patients in hospital - including 50 in intensive care, 22 of whom require ventilation.

NSW Premier Gladys Berejiklian said the worst was yet to come, warning cases were likely to keep jumping in the days ahead.

"I do want to foreshadow that given this high number of cases, we are likely to see this trend continue for the next few days, so just based on the trend in the last few days and where things are going, I am expecting higher case numbers in the few days and they just wanted want to be prepared for that," she said.

The state yesterday recorded 262 new cases and five deaths.

Earlier today, Professor of Epidemiology Tony Blakely delivered a crushing verdict on Sydney's lockdown.

When asked by ABC News Breakfast co-host Michael Rowland this morning what the chances were of the city's lockdown ending at the end of the month as planned, his answer was blunt.

"Zero: It is not going to end," he said.

"The most likely scenario is the lockdown will continue in some form or other, hopefully a little more relaxed for some months, at least two months until the vaccine coverage is upped.

"I realise for the Sydney listeners I'm not bringing you good news, but good news – Christmas and New Year will hopefully be a lot better, as we get the vaccine coverage right and we haven't opened up our border internationally."

Queensland

Queensland has recorded 10 new locally acquired cases of Covid-19 today, as a decision looms on whether lockdown will be extended beyond Sunday.

The new cases have been linked to the Indooroopilly cluster, which has resulted in the infection of dozens of children from three Brisbane high schools and a primary school.

Five of today's cases are household contacts of Ironside State School cases, three are household contacts of Indooroopilly State High School students, and two are household contacts of Brisbane Boys Grammar school cases.

Only two of the new cases were infectious in the community for one day, during the lockdown.

Eleven local government areas of south-east Queensland are in their sixth day of strict lockdown, which chief health officer Jeannette Young hopes she can ease as planned at 4pm on Sunday.

More than 8500 people are in isolation as contact tracers continue to add venues of concern to Queensland Health's list.

The Indooroopilly cluster now numbers 89 cases. Cairns had a brief scare earlier this week when a fully vaccinated marine pilot contracted coronavirus from a container ship in Far North Queensland earlier in the week.

Young said today's case numbers were "very encouraging".

"It is all very reassuring but we have got to keep it up for the next few days, we are not there yet," she said.

"Please continue to come forward and get tested, with any symptoms at all.

"That is critical. And please, keep wearing masks. They have made an enormous difference."

Victoria

Victorians have been warned to expect a "bumpy' few months as the state today recorded four new locally acquired cases, plus two infections announced yesterday.

Professor Tony Blakely told ABC News Breakfast this morning sending Victoria into its sixth lockdown was the only way to control the new cases, even though residents are "sick of it".

"Two separate chains of transmission. We are not sure if they are linked back to the last outbreak. It could be a new outbreak. Too much uncertainty so we've had to into another lockdown," he told the ABC.

"The next couple of months will be bumpy, I fear."

Premier Daniel Andrews announced a snap seven-day lockdown yesterday; the stay-at-home order came into effect at 8pm last night.

Tasmania

Tasmania today recorded a new case of Covid-19 for the first time in 12 months.

The case - a 31-year-old man - travelled to the state from NSW after crossing the Victoria border.

Tasmania Premier Peter Gutwein said the community should not be alarmed, as the man had been in quarantine.

But he did pass through two airport terminals, Melbourne and Launceston. There are concerns for those on his flight, VA1364, that departed Melbourne at 10.40am on August 2.

"Anyone who travelled on that flight should immediately self-isolate and wait for public health to contact them," the premier said.

Gutwein said the man was not given a clearance to travel to Tasmania from NSW.

The man was tested while in hotel quarantine in Launceston before returning to NSW on August 4.

His positive result did not come through until Wednesday morning after he had already left.

The man did not spend any time in the Tasmanian community.