"This week, as predicted, key indicators show the number of cases in NSW are stable or declining which suggests we have passed the peak of the COVID-19 wave," chief health officer Dr Kerry Chant said.

"However, the transmission remains high in the community."

There were 38,610 people diagnosed with COVID-19 across the state this week, a decrease of 5.4 per cent on the previous seven days. Seventy-eight deaths were also reported.

Infections continue to stabilise in Victoria, remaining in the 24,000s for a second successive week after hitting 27,000 earlier in the month.

The state tallied another 100 deaths.

While Australia's largest states may be over the worst, the virus is wreaking havoc in Tasmania.

The state's northwest health service region has escalated its COVID-19 management plan to level two, impacting several hospitals and health centres.

This follows a recommendation based on levels of virus-positive inpatients and COVID-related staff absences, and general demand for services.

South Australia reported 10,474 new cases on Friday, a seven per cent fall compared to the previous week, but chief public health officer Nicola Spurrier said it was still uncertain if the peak had been reached.

"It's still too early to call it. I'm hoping over the next couple of days and the next week, we'll see a more substantial drop," she said.

"I know it would be nice not to be thinking about the pandemic anymore but we certainly still have lots of cases in our community."

Meanwhile, research led by the Centenary Institute and University of Sydney focused on developing a new nasal COVID-19 vaccine has received close to $1 million funding.

The nasally inhaled vaccine is designed to induce immunity in the airways and block virus transmission.

There's an urgent need for new vaccine strategies, chief investigator Professor Warwick Britton said.

"Although approved vaccines substantially reduce severe disease and hospitalisation, there is little evidence they block viral transmission, especially for newly emerging variants," he said.

"This is because current intramuscular vaccines do not stimulate production of virus-neutralising antibodies and T cells in the nasal cavity and airways - sites where infection commences in the body."

A critical part of the research will be the development of a stable, dry powder form of the vaccine to facilitate nasal delivery.

"If successfully translated to the clinic, this vaccine strategy would be a transformative innovation in the fight against SARS-CoV-2, addressing needs not met by current vaccines," Dr Britton added.

WEEKLY VIRUS DATA BY JURISDICTION:

* NSW: 38,610 cases, 78 deaths

* Victoria: 24,238 cases, 100 deaths

* NT: 631 cases, no deaths

* Queensland: 14,241 cases, 12 deaths

* SA: 10,474 cases, 24 deaths

* ACT: 3184 cases, two deaths

* WA: 10,828 cases, 34 deaths

Australian Associated Press