It is the fifth day the state has reported case numbers in the low teens.

But in Victoria, the daily case numbers have continued to yo-yo - they have dropped back to 471 cases and eight deaths on Thursday after reaching 725 yesterday.

A similar pattern was repeated on the two days prior.

Victoria Premier Daniel Andrews said four of the deaths were linked to aged-care.

Two death were men in their 60s, three men and two women in their 80s have died, and one woman in her 90s.

There are now 7449 active cases statewide in Victoria. 1533 of those cases are linked to aged care settings.

Premier Daniel Andrews announced there are a further 109 mystery cases - though he noted these weren't new cases, but discovered through detective work from the past week's announcements.

In its daily update, NSW Health said the source of two of the new cases - a man in Sydney and a teen in Newcastle - were still under investigation.

Eight were household contacts of known cases, one attended the Apollo Restaurant in Potts Point and one attended the Mounties club in Mount Pritchard.

NSW Health is advising the man from Sydney whose case is yet to be linked others dined at the Jambo Jambo African restaurant in Glebe on July 31 from 7pm to 8.30pm.

Anyone who attended at this time is a close contact and should immediately self-isolate until 14 days after they were last there and get tested even if they have no symptoms.

The man also visited a number of inner-city venues, where patrons are being classed as casual contacts. People at these locations during the time and dates indicated should watch for COVID-19 symptoms and, if symptoms occur, immediately get tested and self-isolate until the test results are retuned as negative.

These venues include:

In Newcastle, the teenager attended St Pius X High School while infectious. The school has been closed for cleaning and contact tracing is underway.

The teenager also caught the Number 26 bus from Hamilton to Adamstown on August 3, at 8.20am and NSW Health is advising that all people on the bus at this time are close contacts and should immediately self-isolate until 14 days have passed and get tested even if they have no symptoms.

The teenager is also a member of the Newcastle Jets under 15's representative squad which played a soccer match against the Stanmore Hawks at Arlington Oval in Dulwich Hill on 1 August. Members of both teams are considered close contacts and are also required to isolate for 14 days.

Late on Wednesday evening - after the deadline for the daily case numbers - NSW Health reported that a man in his 20s - a relative of the teenager - also tested positive, after visiting a number of Newcastle venues.

Anyone who attended the following venues at the specified times to immediately self-isolate and seek testing:

Any patrons who visited the following venues at the times specified should be alert for symptoms, and if any develop to get tested and self-isolate immediately:

Public Health Controller for Hunter New England Health's COVID-19 response Dr Kat Taylor said officials were still working to identify any further contacts or venues visited by both individuals, and further updates would be provided as more information becomes available.

"It is vital people in the community continue to present for testing if experiencing symptoms to limit the spread of the virus," she said.

"I encourage everyone to follow directions they receive about home isolation and quarantine, and maintain COVID-safe practices of physical distancing, coughing or sneezing into their elbow, and regularly washing their hands."