The confirmed coronavirus cases in each of Australia's states. Source: Australian Medical Association

Why the rise in virus cases is 'good news'

Deputy Chief Medical Officer Paul Kelly has called the dramatic rise in Australia's COVID-19 cases "good news", for one particular reason.

The potentially deadly disease has infected more than 2300 Australians - most of them in NSW - and killed eight people, forcing the Federal Government to take increasingly drastic measures to help slow the virus outbreak.

While the increasing number of cases is "obviously worrying and we are concerned", Professor Kelly said that "on one side, that is good news" because it means "we are finding the cases and they are still mostly coming from overseas".

He pointed out today that the majority of confirmed coronavirus cases have been mild, and only 197 people - or less than 10 per cent of those infected - "have been hospitalised because they are sick".

"We are not overwhelming the system," Professor Kelly said.

He said that the uptick in cases over the recent days was largely a result of the Ruby Princess cruise ship, which docked in Sydney last Thursday.

More than 130 passengers from the ship have now tested positive to COVID-19, and a 77-year-old female passenger died in hospital yesterday of the virus.

Reporters grilled NSW Premier Gladys Berejiklian this morning about why the ship was allowed to dock in Sydney, with NSW shadow minister for home affairs Kristina Kennelly calling the situation "disastrous".

Ms Kennelly questioned why the ship was allowed to dock despite apparent orders from Prime Minister Scott Morrison four days earlier, banning ships from foreign ports.

The rest of the new cases, Professor Kelly said, "are being found as part of the contact tracing exercise", praising the "fantastic work being done by the states and territories" to monitor the number of virus case numbers.

The process is being used to understand how COVID-19 is spreading throughout communities by figuring out who the infected person caught the illness from, and who they've been in contact with while infectious.

While community transmission of coronavirus is still quite low in Australia, Professor Kelly warned that if Aussies didn't follow the new measures put in place by the government, we would continue to see a significant rise in cases.

He said that on average, a person with an infectious disease will infect three other people.

"Just imagine that - if we did not take any of the measures about social distancing and decreasing the mixing that we do on a daily basis, then one person with the disease not taking any of those social distancing or hygiene messages seriously will infect three people," he said.

"Every one of those three people if they do not take those messages seriously will infect another three people and so on."

Professor Kelly said implementing social distancing and decreasing the number of interactions between people is how Australia is going to flatten the curve.

"All of these fit together to decrease the transmission from person-to-person of an infectious disease," he said.

"And if we do that, we will get on top of it."

Originally published as SURPRISING ADMISSION: Why the rise in virus cases is 'good news'