New South Wales has recorded 24 new locally acquired cases of COVID-19

Premier Gladys Berejiklian revealed NSW recorded 24 new locally acquired cases of coronavirus in the 24 hours to 8pm on Wednesday with 17 linked to previously confirmed cases.

However it is seven mystery cases that have health officials concerned.

"Seventeen of these cases are linked to previous ones, with 11 of them being household contacts," NSW chief health officer Dr Kerry Chant said.

"Seven cases reported remain under investigation."

Adding to the state’s worries is that NSW continues to record Covid-19 cases who have not been in isolation, with fears more exposure sites and cases will pop up.

"In relation to the 24 new locally acquired cases, 12 were in isolation throughout the infectious period, and a further nine were in isolation for part of the infectious period," Dr Chant said.

"This still means we are still seeing cases in the community."

Premier Berejiklian said it was "cause for concern" that a dozen cases had been out in the community while infectious.

"In too many examples we are seeing workers who are leaving the house with symptoms or going to work with symptoms," she said.

"Then inadvertently as they are going about shopping or other activity, they are passing it onto others."

Ms Berejiklian said the target was to have a majority, or all, of new cases recorded in isolation.

"If we want the lockdown to succeed, all of us to have minimise our movements," she said.

"All of us to have minimise our interaction with others, as difficult as that is, to make sure that the lockdown is successful."

Of the 24 new cases announced on Thursday, one was a healthcare worker who worked at Fairfield Hospital and Royal North Shore Hospital while infectious from June 24 to 28.

A household contact of the nurse was also included in Thursday’s numbers, while more than 200 staff and patients have been identified as close contacts to date.

One new case was linked to Crossways Hotel, brining that cluster to eight, including six people who acquired it at the venue and two subsequent contacts.

One new case was linked to Joh Bailey Double Bay with that cluster growing to 13, including nine people who acquired their infection at the venue and four subsequent contacts.

One new case was linked to Lyfe Café Bondi Beach and the total there is now 25 cases, seven being infected at the café and 18 of whom were subsequent contacts.