New South Wales recorded 633 new locally acquired Covid-19 cases in the 24 hours to 8pm yesterday.
It is the largest daily total every recorded in the state.
NSW Premier Gladys Berejiklian confirmed three people with Covid-19 have died.
A man in his 60s from south-western Sydney died after being infected with Covid-19 at Liverpool Hospital. He is the ninth death linked to that outbreak.
Two men, both from Western Sydney and in their 70s, died at Nepean Hospital.
There have now been 60 deaths linked to the Delta outbreak that began in June, and 116 in NSW since the start of the pandemic.
"What the data is telling us in the last few days is that we haven't seen the worst of it," Berejiklian said.
"And the way that we stop this is by everybody staying at home."
Of the new cases, 224 are from the South Western Sydney Local Health District (LHD), 216 are from Western Sydney LHD, 54 are from Nepean Blue Mountains LHD and 52 are from Sydney LHD.
The virus continued to spread through regional areas, with new infections identified in Dubbo and several surrounding towns, the Hunter New England LHD and Broken Hill.
The premier said there was particular concern about the virus spreading in the Sydney suburbs of Merrylands, Guildford, Auburn, Greenacre, St Marys and Strathfield.
"We obviously remain concerned about western New South Wales, especially in our remote Indigenous communities and we just are calling out anybody who was in Wilcannia in the last little while needs to come forward and get tested," she said.
NSW chief health officer Kerry Chant said the data showed that each person infected was passing on the virus to more than one person.
"I can't express enough my level of concern at these rising numbers of cases," she said.
There are 462 people with Covid-19 in NSW hospitals, 77 of them are in intensive care with 25 of those on ventilators.
Chant said those in hospital included patients in their teens up to those in their 80s.
"We know that for every one of those individuals in ICU, particularly those in the older age groups, they have a real and material risk of death.
"We will see more admissions and more deaths if these numbers continue to increase."
There were 94 cases were in isolation throughout their infectious period and 30 were in isolation for part of their infectious period.
Sixty-two cases were infectious in the community, and the isolation status of 447 cases remains under investigation.
Police found at least 400 examples yesterday of people who had left their homes while they were supposed to be isolating.
One man was given a $AU5000 fine after telling police he was putting the bins out, but had in fact left his property.
"Imagine if out of those hundreds and hundreds of people doing the wrong thing, a couple have a virus and going around the community spreading it, that sets all of us back," Berejiklian said.
Police issued 736 penalty infringement notices yesterday to people breaching the public health orders.
There were just under 103,000 tests taken in the reporting period.
- ABC