ABC NewsRadio has been speaking with Deputy Chief Medical Officer Michael Kidd

AFP: Saul Loeb

Professor Kidd said he doesn't believe we're "missing a lot of cases with the testing we have underway".

"Testing is increased in situations where people may be affected by coronavirus," he added.

"We've only been sharing our planet with this virus for the past 3-4 months. There's still a lot we're learning about the coronavirus.

"It's very early in the development of a vaccine."

On the issue of masks, Professor Kidd said: "Masks are mainly to protect the environment from the wearer. We've had shortages of masks, especially masks used in healthcare settings."

The Deputy Chief Medical Officer also said while our borders are closed, "it's not the time to lift the measures we have in place."

And if you've had COVID-19, Professor Kidd said: "Those people will still need to be doing the same … physical distancing, hand hygiene, etc."

Why aren't we attempting herd immunity?

"If we attempt herd immunity we would end up with a very large number of people severely unwell and a very large number of people would die so we're not going down a herd immunity approach in Australia," Professor Kidd said.