Australia has been using swab tests to confirm cases of the deadly virus and pathologists have warned against the use of a new finger-prick test, being imported into Australia, which is less reliable in detection of “early” COVID disease.

On the total number of tests internationally Australia is behind only South Korea, where about 410,600 had been completed by this week, a rate of about 800 tests per 100,000 people.

Canada has completed more than 225,700 test (about 600 per 100,000), ahead of the United Kingdom with almost 135,000 (less than 200 per 100,000).

Positive tests lowest in the world

Australia's positive test rate is the lowest in the world at 1.9 per cent, compared with 2.4 per cent in South Korea and 3.3 per cent in Canada.

As of Wednesday afternoon there were 4858 confirmed cases and 21 deaths recorded in Australia.

University of Queensland influenza researcher Kirsty Short said Australia's high rate of testing was key to managing the virus spread.

"I think one of the biggest strengths that we have as a country is that we've got incredible rate of testing, relative to our population," she said.


"What we've seen from South Korea is they managed to get it under control just with extensive testing. From that perspective there's lots of positive signs, but of course we need people to practise social distancing and follow government guidelines.

"If people follow the rules the government is mandating, then I feel pretty positive."

Dr Short – who is conducting research into COVID-19 – said the risk from unknown infection sources was becoming more evident through scientific research.

"The data suggests currently that a large percentage of the population could be infected but asymptomatic," she said. "That means you would feel fine, go about your daily business but you would be unwittingly spreading the virus.

"That's a really big problem because if you don't know you're infected, then you're still going outside and interacting with people as if you weren't infected."

She said the percentage of people with asymptomatic infection was variable, but likely represented "a significant proportion of individuals".


"I've never seen science move this fast in my whole career. The science is progressing really, really fast," she said.

Deputy Chief Medical Officer Paul Kelly said there were some early indications that “the curve is, in fact, flattening”.

“We haven’t had a large increase in the last 24 hours, although the numbers continue to increase," he said.

Professor Kelly appeared to walk back a promise to release modelling being used to guide the federal government's massive response to the virus.

He said the limited numbers published daily by the Health Department were being used by the national cabinet.

NSW is ahead of all other jurisdictions on testing, and was due to pass 100,000 on Wednesday.

Queensland has conducted more than 50,000 tests, while Victoria has completed more than 45,000 tests and South Australia more than 27,300.