Of the 19 coronavirus cases reported on Wednesday, 10 were connected to the Thai Rock Restaurant at Wetherill Park, taking the size of that cluster to 85.

Its Potts Point sister restaurant is connected to two additional cases, taking the size of a cluster in the densely populated eastern Sydney suburb to seven, with one new case also linked to nearby restaurant The Apollo.

NSW Health is yet to establish any link between the two Thai Rock restaurant cases and is still investigating.

A further two cases - a woman in her 30s and another in her 60s - were also confirmed in Port Stephens on Wednesday.

Two are close contacts of the man in his 30s from the area who was announced last week. They are isolating at home and the community is reminded to monitor their symptoms and remain on high alert.

Executive director of health protection Dr Jeremy McAnulty said the state was at a "knife's edge" given clusters were now popping up outside southwest Sydney.

"This is concerning and that's why we need everyone in the community to do their bit," he told reporters on Wednesday.

Just two of the 19 cases on Wednesday were in hotel quarantine.

The caseload prompted Queensland Premier Annastacia Palaszczuk on Wednesday to ban all Greater Sydney residents from the state from Saturday.

NSW Premier Gladys Berejiklian said "it would have been nice" if her Queensland counterpart had notified her of the ban before announcing it.

Other restrictions imposed on NSW residents include a ban on entering Western Australia unless an exemption is granted, while travel to South Australia and Tasmania is permitted, but people must quarantine upon arrival for 14 days.

Travel to the Northern Territory and the ACT is allowed but people travelling from hotspots must quarantine for 14 days, while NSW residents who return from Victoria must self-isolate for 14 days upon return.

Ms Berejiklian reiterated the state was on high alert and urged people to do the right thing by keeping 1.5 metres away from one another and wearing a mask where social distancing was not possible.

"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," she told reporters.

"If we don't all do the right thing, we will go down the path of having more cases and then having to consider additional measures to reduce those cases."

Tighter restrictions will be in place for gyms from Saturday, including the requirement of a permanent on-site hygiene marshal to ensure social distancing, equipment cleaning and hand sanitiser availability.

This includes 24/7 gyms that are otherwise unstaffed at certain periods.

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 infected Thai Rock Potts Point diners also visited the nearby Cruising Yacht Club Australia in Rushcutters Bay on July 23, 24 and 26.

The prestigious members-only club, which is the home of the annual Sydney-to-Hobart race, has closed until August 1 for deep cleaning.

Several other restaurants in the eastern Sydney suburb have voluntarily shut down as a precaution, while all residents and visitors to Potts Point have been asked to get tested if they experience respiratory symptoms.

Bayanami Public School in Parramatta, meanwhile, was closed on Wednesday for contact tracing and cleaning after a student tested positive.

Australian Associated Press