Australians are being warned to expect long COVID-19 testing queues and wait times for at least several more weeks, as pathology labs continue to be hit by huge demand and staff shortages around the country. 

Driving the surge in cases is the highly transmissible Omicron variant, with New South Wales today recording 35,054 cases and Victoria 17,636, both significant spikes compared to previous days.

Medical experts suggest there are now many COVID cases not included in the official daily figures due to difficulties in accessing PCR testing. 

Despite pleas from leaders to only get a traditional PCR test if you're identified as a close contact, have symptoms, or have tested positive on a rapid antigen test, the growth in case numbers means there's been little let-up at testing sites because the number of people who fit that criteria remains large. 

Why has testing become an issue?

The answer depends on where you live. 

But, generally, it's simple: The spike in cases means there is more demand for tests.

Bond University director of the institute for evidence-based healthcare Paul Glasziou said the rise in cases originally coincided with borders reopening and people needing PCR tests to travel.

The surge in demand for tests came after an extremely quiet period, catching some testing facilities off guard.

Dr Glaziou said that pressure combined with the Omicron outbreak to overwhelm testing sites, creating a bottleneck that, he feared, would stick around.

"My guess is that [testing problems] are going to be an ongoing problem until we reach the peak [in cases]," he said. 

Deputy Chief Medical Officer Sonya Bennett said on Tuesday that the peak in cases was expected next month.

COVID-19 has also affected pathology services, with staff falling ill, forcing some labs at testing sites to operate at reduced capacity or to close entirely.

"So, we had less capacity within the system over the Christmas-New Year period to cope with this Omicron demand," Dr Bennett said.

In Australia, PCR tests need to be conducted by a trained medical professional. This is not the case in the United Kingdom where PCR tests can also be done at home and sent off to pathology labs in the mail, reducing some of that burden on health staff.

Another cause for the delays is how those swabs are screened.

This week, Victoria's COVID-19 response commander Jeroen Weimar said PCR tests were typically screened in batches, as opposed to one test at a time.

When a batch indicated a positive swab, all tests within that batch would then be screened to find the positive case or cases.

"Because of the very high rate of positivity we're now seeing in all of our tests, every single test is processed individually, through all of our labs, that means that it takes us longer to process individual test results," Mr Weimar said

"That means we're starting to see longer turnaround times."

Then there is human error.

With staff at pathology services working under heavy pressure for an extended period of time, health authorities say burnout and human error are to be expected. 

One example was in South Australia where nearly 100 COVID-19 swabs and blood samples temporarily went missing en route to being processed.

Delays in results have also meant some people returned for more testing, assuming their original swab had been lost. 

There are also anecdotal reports of patients receiving false-negative results, despite feeling unwell and returning positive rapid antigen tests. Again, many of those people return for follow-up testing.

Is planning an issue?

Since last month, Australia has put more reliance on rapid antigen tests [RATs] for an initial diagnosis. 

Government leaders agreed RATs would be an important tool used to take pressure off PCR testing as cases increased. 

Unfortunately, there was a stock supply and distribution issue.

While RATs had been used overseas since mid-last year, they were only approved for use in Australia in November. Soon after, the Omicron variant struck, which added more demand for RATs globally.

Some states and the federal government have now placed orders to replenish depleted stock, with more rapid tests due to arrive this month.

The Prime Minister said testing was an issue for the states.

He said he had no intention of making tests available for free from the national stockpile unless people fitted the criteria set out by the government.

That saw businesses step in to fill the void.

"As would be expected, you ended up having price-gouging of the rapid antigen test," the Grattan Institute's health and aged care program director, Stephen Duckett, said.

The Grattan Institute penned a report in July warning there would be a reliance on RATs, especially for settings such as schools. 

"With a bit of foresight, you could see that rapid antigen tests were going to be needed. So, we didn't plan for that," Professor Duckett said.

"We hadn't procured enough of them, despite warnings that we'd still need them. And, so, we've got a rapid antigen test disaster, and it is entirely inequitable because, of course, people on low incomes can't afford to pay $15 a test and then get told you have to test yourself five times."

As a result, people are turning back to PCR tests, he said. 

Professor Glasziou noted breakdowns in systems were always expected during a pandemic.

But, he said, it was important to remember that testing was only ever meant to be one part of the pandemic-response strategy. 

He said social distancing, masks, contact tracing and isolation could help to reduce pressure on the overall health system and the community. 

"We need to try and flatten that [curve], mostly because … as we've seen in New South Wales, the number of people going into hospitals and also the loss of health care workers [has become] a key problem," he said.