“There is no question that the hospital system is under enormous pressure across NSW,” the state’s health minister Brad Hazzard acknowledged on Tuesday.

But he insisted that overall the system was “still extraordinarily good”.

In recent days, four cancer patients, a nurse manager and a junior doctor have tested positive for the virus at southern Sydney’s St George Hospital. Twenty-one patients are isolating, as are 80 health workers.

Hazzard said the case was “fairly indicative” of the way COVID-19 is affecting hospital staff.

“Unfortunately all our health staff are finding they’re on the receiving end of having to be taken offline because they’re potentially exposed,” he said.

He asked the community to be tolerant and understand that health staff were working hard, “but we’re in a pandemic and people will have to be taken offline and we will have to have some inconvenience”.

Long delays at Westmead Hospital’s ambulance bay on Monday night forced paramedics to do paperwork on the concrete parking lot floor decked out in full protective gear, their union says.

The Australian Paramedics Association (NSW) says one patient had to be X-rayed while stuck in the ambulance bay, where up to 13 vehicles were waiting for hours.

The ambulances were mainly transferring COVID-19 patients to the hospital.

“These kind of scenes don’t belong in a functioning first-world healthcare system,” APA NSW President Chris Kastelan said in a statement.

He said NSW Health had failed to provide for the basic needs of frontline workers, and the logistics and capacity for COVID-19 patients should be better by now.

At least one ward has been closed at Canterbury Hospital at Campsie after transmission occurred.

More than a dozen patients have tested positive for the virus in recent days in an outbreak at Nepean Hospital.

BreastScreen NSW announced on Tuesday it would suspend all routine breast screening across NSW because of the outbreak.

NSW reported 452 new local COVID-19 cases on Tuesday, and the death of a woman in her 70s.

Premier Gladys Berejiklian warned the case numbers would get worse and that September and October would be “our most difficult months”.

The steady increase in new cases has led NSW Health’s contact tracing team to stop identifying most exposure sites in Sydney, focusing instead of the regions.

NSW Health’s Jeremy McAnulty said on Tuesday that for the last few days the government had focused just on places where they believe there is a high risk of transmission, leaving out lower-risk places like supermarkets and shopping centres.

“We’ve learned that people get lost in the detail when we put up venues that we don’t think are risky places on the website or in the media,” McAnulty said.

“We’re really trying to focus the public’s attention on those where we believe there’s a true risk.”

A number of schools have been forced to close in recent days because of COVID-19 outbreaks.

Kings Langley Public School in the city’s northwest will be closed for cleaning and contact tracing following a positive test.

Bankstown and The Meadows Public Schools will reopen on Wednesday after students or teachers tested positive.

Meanwhile, NSW Police are warning Sydney residents against joining in anti-lockdown protests schedule for Saturday, threatening arrests and fines for those that breach stay-at-home rules.