COVID cases have hit a four-month high in NSW as Premier Gladys Berejiklian admits to anxiety about the spread of the virus.

NSW reported 22 more infections on Tuesday – its highest number since 29 were confirmed on April 16.

“It is a daily battle in NSW; we have to be on our toes, we are in a state of high alert,” Ms Berejiklian said.

“My anxiety has not subsided in relation to what a knife’s edge NSW is on.”

Four of Tuesday’s cases are returned international travellers in quarantine, while two more are in people who have entered the state from Victoria.

But eight are from a new cluster at an independent Catholic school in north-west Sydney – where the source of infection is yet to be traced. NSW Health Minister Brad Hazzard confirmed to the ABC on Tuesday that the outbreak had grown to 17 infections.

“At this stage further investigation will, perhaps, give us further clarity at how that’s all occurred,” Mr Hazzard said.

“It’s not always possible to determine the source and that’s what worries us most.”

Earlier, Victoria confirmed another 331 infections and 19 more virus-related deaths on Tuesday morning. Along with the 19 fatalities reported on Monday, it is Victoria’s deadliest two days in the pandemic.

However, daily infection numbers appear to be falling as the state’s tough virus restrictions take effect.

Victoria’s COVID-19 toll is now 246, while the national toll is 331.

Australia’s deputy chief medical officer, Michael Kidd, has warned virus deaths will keep rising even if Victorian infections stabilise further.

“We are seeing the first promising signs of a reduction in daily numbers of cases but it is too early to be certain,” he said.

But more heartbreak lies ahead for families.

“There is a seven to 10-day lag between the daily reports in numbers of cases and people dying,” Professor Kidd said.

“For many people, it is a week or more after they have been infected that we see people who are gravely unwell.”

Victorians have been warned that COVID fatalities will likely rise further.

NSW schools forced to close

In NSW, authorities say the source of the escalating outbreak at Tangara remains unclear. All of the school’s students and staff are in self-isolation and being tested.

The Opus Dei-associated school has closed its secondary campus until August 24 and its junior campus until at least Wednesday.

Elsewhere, two South Coast schools have also closed after three new confirmed coronavirus cases.

NSW health authorities say one student from Batemans Bay Public School and two students from Batemans Bay High School have tested positive to the virus.

“All staff and students are asked to self-isolate while contact tracing occurs,” a statement from the high school read.

“They’re likely to both reopen on Wednesday for on-site teaching and learning,” the NSW Department of Education’s Murat Dizdar told the ABC.

The Batemans Bay outbreak comes several weeks after an earlier cluster linked to the town’s soldiers’ club grew to eight cases.

NSW Health will set up a pop-up coronavirus testing clinic in the town for the rest of the week.

NSW chief health officer Kerry Chant has urged people to avoid large gatherings. On Monday, she admitted older school students are more likely to transmit the virus.

On Tuesday, Ms Berejiklian reiterated the high alert in NSW, following the Victorian outbreak.

“We are in a pandemic – every organisation, every entity needs to abide by the COVID-safe plans,” she said.

A queue for virus testing in Batemans Bay in July. Photo: Getty

Premier grilled at inquiry

Early on Tuesday, Victorian Premier Daniel Andrews was grilled at a parliamentary inquiry into his government’s response to the pandemic.

Inquiry deputy chair Richard Riordan honed in with questions about the state’s botched hotel quarantine program, which is blamed for the second wave.

On Tuesday, Herald Sun reported a leaked video of bureaucrats from the state Department of Jobs, Precincts and the Regions congratulating themselves on pulling together the program and the efforts made to make guests comfortable.

The video shows no discussion of health restrictions.

“Did the crisis cabinet think hotel quarantine would be better run by people who fix roads and run an art gallery than your own health department?” Mr Riordan asked.

“The answer to your question is no. At no point did people make a decision like that,” Mr Andrews said.

State Health Minister Jenny Mikakos, chief health officer Brett Sutton and Department of Health and Human Services secretary Kym Peake were also to appear before the inquiry on Tuesday.

-with agencies