NSW records 11 new COVID-19 cases as state in "scariest period" yet

With New South Wales recording 11 new locally acquired cases of COVID-19 today, Premier Gladys Berejiklian has described the situation as the state's "scariest period" of the pandemic to date.

Of the new cases all but one are linked to known infections, but that does not mean Berejiklian is falling into complacency.

The Premier today was deemed a casual contact of a confirmed infection, forcing her briefly into isolation this morning until she received a negative COVID-19 result.

That came after the NSW Agriculture Minister Adam Marshall tested positive for COVID-19 overnight, prompting a 'stay put' directive for Parliament while Health Minister Brad Hazzard went into isolation too.

"Since the pandemic started this is perhaps the scariest period that New South Wales is going through, and Dr Chant and I are on equal view on that," the Premier said.

"I do want to stress that my level of concern is medium to high across New South Wales."

The one unlinked new locally acquired COVID-19 infection is a hairdresser who works at a Joh Bailey salon in Double Bay.

Chief health officer Dr Kerry Chant says the contact tracing team is currently working on identifying how the hairdresser may have become infected.

"We will be doing that backward tracing and calling out any people in the upstream - what we call upstream contact tracing - to flush out any unrecognised chains of transmission," Dr Chant said.

"At the beginning of the day we often start with unlinked cases but as you can see those linkages have been made and by the time we closed off the numbers we were able to report that 17 of those 18 cases were all linked."

With NSW having conducted 48,402 tests yesterday the chief health officer has called on the population to sustain and surpass the high level of testing to quash the outbreak.

"What I'd like to see is for a week those testing number are sustained at those levels, or even surpassed," Dr Chant said.

"So please, it is incredibly important at this time that we flush out any unrecognised chains of transmission."

Updated at 1.01pm AEST on 24 June 2021.