Three Newcastle pubs and a drug court in nearby Toronto have also been shut for deep cleaning after people from Sydney visited while infectious with coronavirus.
NSW health authorities on Sunday confirmed a case connected to Sydney's Potts Point cluster worked at Toronto Drug Court last Monday.
The court underwent deep cleaning on Sunday and everyone who was at the court that day should monitor themselves for symptoms.
Another man who had visited Sydney and picked up COVID-19 visited Newcastle venues Hotel Jesmond last Wednesday and Wallsend Diggers and the Lambton Park Hotel on Thursday, with all three venues to undergo deep cleaning.
Patrons at certain times on those dates must now self-isolate for 14 days and get tested.
"This action is vital to limit the spread of the virus," Hunter New England Health's Dr David Durrheim said in a statement on Monday.
Three Newcastle pubs, Toronto court shut as NSW records 13 new coronavirus cases
Wallsend Diggers chief executive John Hume said he was contacted by NSW Health on Sunday and due to coronavirus regulations every visitor on that evening had been identified. The club is expected to reopen on Monday.
The NSW government is strongly recommending people wear masks in high-risk situations as the state enters a critical phase in the battle against coronavirus.
Public-facing workers, worshippers, people living near community clusters and those in enclosed spaces, such as on public transport or in grocery stores, should wear face masks.
"They're recommendations to make sure we keep NSW in the position we are in. I cannot stress enough how critical the next few weeks are," Ms Berejiklian told reporters on Sunday.
She stopped short of making masks compulsory but said elderly people or those suffering underlying health issues should also wear masks.
"We have been talking about masks for several weeks but obviously the persistent situation in Victoria gives us cause for alarm," she said.
An 83-year-old man connected to the Crossroads Hotel cluster in southwestern Sydney died at the weekend, taking the NSW death toll to 52 and the nationwide tally past 200.
It was the first coronavirus-related death in NSW since late May.
People in Australia must stay at least 1.5 metres away from others. Check your state’s restrictions on gathering limits.
If you are experiencing cold or flu symptoms, stay home and arrange a test by calling your doctor or contact the Coronavirus Health Information Hotline on 1800 020 080.
News and information is available in 63 languages at sbs.com.au/coronavirus