Victorians from Friday will be able to use rapid antigen tests to prove they have COVID-19 and be required to report positive results to the government.
The Tasmanian government has also announced it will shift to rapid antigen tests as the primary method for diagnosing COVID-19 cases.
The new measures come into effect as PCR testing clinics come under unprecedented strain across the country and as Prime Minister Scott Morrison defends the government's supply of RATs.
Victorian Health Minister Martin Foley is signing off on a new "probable case" category of contact on Thursday, imposing the same rights and obligations as anyone who tests positive with a PCR test.
That will come into effect from Friday morning.
"In the eyes of the health department, you have COVID," acting chief health officer Ben Cowie said of those receiving a positive result from a RAT.
Probable cases must immediately isolate for seven days and notify their contacts.
It will be mandatory to report the result by calling the department or filling out an online form, expected to go live on Friday.
Professor Cowie said those people were being discouraged from confirming the result with a PCR test unless they have no symptoms and are not a contact of a positive case.
"They are the least likely to actually have COVID and that confirmation can be sought if there's an unexpected positive RAT result," he said.
Health Minister Martin Foley said people who return a positive RAT will receive the same clinical and financial support as those with positive PCR results.
"The goal is to bring it as close to, if not exactly the same as, the supports that the PCR reporting system has and make sure that increasingly, the rapid antigen testing is the key part of our testing," he said.
Probable cases will be reported alongside the daily figures.
Tasmanian Premier Peter Gutwein announced on Thursday his state will also shift to RATs as the primary tool for diagnosing coronavirus.
"Tasmania will shortly be moving to rapid antigen testing as the primary diagnostic tool to detect cases of COVID-19," he said in a statement.
He said people who test positive on a RAT will be considered a case of COVID-19 and will be subject to the same requirements as a positive PCR-recorded case.
Mr Gutwein said RATs will be free to anyone in Tasmania in the same way PCR testing has been.
Anyone requiring a test - people who are symptomatic or a close contact - can arrange a RAT or PCR test by contacting the public health hotline.
Mr Gutwein said people who return a positive RAT must register their result through the public health hotline or the state's coronavirus website.
Mr Morrison on Thursday rejected suggestions the country was left underprepared for worst-case scenarios despite extensive modelling on various possibilities by the health department.
"I don't accept the suggestion that they haven't been doing their job. I think they've been doing their job extremely well and under extraordinary pressure in a very uncertain environment," he told reporters on Thursday.
The Prime Minister said the whole world has been under pressure from the Omicron variant and scrapping for test supplies.
The prime minister rejected the assertion the country was left underprepared for worst case scenarios despite extensive modelling on various possibilities by the health department.
"I don't accept the suggestion that they haven't been doing their job. I think they've been doing their job extremely well and under extraordinary pressure in a very uncertain environment," he told reporters on Thursday.
He pulled up just short of laying the blame at the feet of states and territories.
Prime Minister Scott Morrison speaks to the media. Source: AAP
"States secure the supply for PCR tests and rapid antigen tests," he said. "It was discussed at national cabinet in November ... so there was no confusion.
"I'm not making a criticism of the states. I am just saying that you asked me whether the Commonwealth had done what is needed to do and I said, 'Yes we had' and now we are going further."
Criticism continues over the availability and affordability of RATs after meeting.
People who test positive on a RAT don't have to get their results confirmed with a PCR test in the hopes of easing pressure on overwhelmed clinics.
However, University of Melbourne epidemiologist Tony Blakely has warned surveillance will not be as accurate going forward with the tests mainly being done at home.
"The horse has bolted, this is the biggest policy failure so far in Australia," he told the Seven Network on Thursday morning. "We also haven't thought about how you can load up that data to the surveillance system, so we won't get that in place in the next couple of weeks."
Mr Morrison said it was more important to connect people with care than reporting case numbers.
"Case numbers are less of an issue (and) will be underestimated in Australia because we know that people are self-managing in many instances," he said.
"What matters first is that people who have COVID (is) the care they get connected to."
Mr Morrison noted national cabinet is working through how to more accurately record case numbers so hospitals were able to prepare.
The Prime Minister said on Wednesday 200 million rapid tests would be available in coming weeks but ruled out making them universally free, instead providing 10 tests over a three-month period to concession cardholders.
