The restaurant's sister Thai Rock in Potts Point was connected to two additional cases, taking the size of that cluster in the densely-populated eastern Sydney suburb to seven. One new case was also linked to the nearby The Apollo eatery.
NSW Health has yet to establish a link between COVID-19 cases at the two Thai Rock restaurants and are still investigating.
Just two of the 19 cases on Wednesday were in hotel quarantine.
One of Prime Minister Scott Morrison's senior advisors, Nico Louw, posted to Instagram on Tuesday to say he was self-isolating as he was a close contact of a confirmed case linked to The Apollo.
NSW Senator Hollie Hughes has also been told to monitor for symptoms after she attended the Thai Rock restaurant in Potts Point, which has been linked to a number of cases.
The caseload has prompted Queensland Premier Annastacia Palaszczuk on Wednesday to ban all greater Sydney residents from the state from Saturday.
"NSW is holding the line but as I've been saying for a number of weeks, we're at a critical stage of the pandemic," Premier Gladys Berejiklian told reporters.
Gyms in NSW meanwhile will be compelled from Saturday to register a COVID-safe plan and have a dedicated hygiene marshal on-site to ensure social distancing, equipment cleaning and hand sanitiser
This includes 24/7 gyms which are typically not staffed at all times.
Fitness First gym in Kings Cross on Tuesday confirmed one person who attended the gym for a class on July 20 had tested positive.
Two more pop-up COVID-19 testing clinics have also been set up in Sydney's east as NSW health authorities monitor the Potts Point cluster.
A clinic opened up in Surry Hills on Tuesday and another will open from noon on Wednesday in Rushcutters Bay Park, down the road from Potts Point.
Two infected Thai Rock diners visited the nearby Cruising Yacht Club Australia in Rushcutters Bay on July 23, 24 and 26, with the venue's staff to be tested.
The prestigious members'-only club, which is the home of the Sydney-to-Hobart annual sailing race, has closed until 1 August for deep cleaning.
A number of other restaurants in the eastern Sydney suburb have voluntarily shut down as a precaution.
All residents and visitors to Potts Point have been asked to seek COVID-19 testing if they experience any respiratory symptoms.
A primary school in western Sydney, meanwhile, will be closed for at least one day after a student tested positive to COVID-19.
Bayanami Public School in Parramatta will be closed on Wednesday to allow time for the school to complete contact tracing and cleaning.
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.
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