SYDNEY - The number of confirmed COVID-19 cases in Australia has reached 100, Federal Health Minister Greg Hunt announced on Tuesday.

"Within Australia we now have 100 officially confirmed cases and sadly there have been three lives lost," Hunt said.

The figure includes a number of patients who have subsequently recovered from the disease and does not include hundreds of people currently awaiting test results.

Following a ramping up of containment measures in Italy, Hunt said that Australian authorities would consider introducing more rigid restrictions on arrivals from the country.

Australia's Chief Medical Officer Brendan Murphy reiterated that the majority of those testing positive in Australia had either recently travelled from overseas, or been direct contact with somebody who had.

"In Australia ... we've continued to have some cases that have come from contact with imported cases, continued cases imported from a range of countries, and some additional cases from the community transmission event that's happened in northern Sydney," Murphy said.

"New South Wales (NSW) and Sydney is still the significantly biggest part of our outbreak in Australia."

An additional eight cases of COVID-19 were confirmed in the state of NSW on Tuesday, taking the total cases there to 55, while Victoria reported another three cases, taking their total to 18.

Two of those who have passed away from the disease were residents at a Sydney aged-care-facility, while the other was a 78-year-old man who was evacuated from a cruise ship and passed away in Western Australia last month.

Australian schools have emerged at the center of the latest jump in cases, with four schools shut down after students tested positive to the disease.

Last week a 16-year-old boy became the first student in Australia to test positive for the virus, with authorities taking the precaution of closing his school on Friday.

The school was reopened on Monday, however 69 students and staff who had close contact with the teenager were told to self-isolate for 14 days.

Also on Monday, three more students from two other Sydney schools were confirmed to have the virus, with those schools remaining closed on Tuesday as authorities sought to contain a potential outbreak.

"NSW Health is contacting close contacts of the three children to advise them to self-isolate and seek medical advice if they become unwell," the department said in a statement.

In the State of Victoria an elite private school was closed on Tuesday, with this time a teacher at the school testing positive for the disease.

"We are now going through the process of mapping the potential spread of the virus within the school with a view to then making contact with families and identifying anyone who could have been impacted," school principal Jonathan Walter told reporters.

Murphy said that officials were not advising that general members of the community, even those with acute respiratory symptoms including cold and flu, be tested for the disease due to the low instances of community transmission in Australia.

"Our focus at the moment is testing people who are returned travellers who have acute respiratory symptoms - cough, sore throat - and contacts of confirmed cases," Murphy said.