At this stage, health officials have not extended the restriction to all travellers from Europe or the USA, but this will be reviewed on a week by week basis.

Italy is the latest country to be included in the ban, with it currently grappling with the largest outbreak of the virus outside China.

The extension means foreign nationals who have been in any of the four nations will not be allowed into Australia for 14 days from the time they left those countries. Australian citizens and permanent residents travelling from those countries will still be able to enter Australia but must self-isolate for a fortnight after returning home.

Federal Health Minister Greg Hunt said travel restrictions had been extended by Cabinet's national security committee based on advice from the nation's chief medical officers. "The committee has decided to reaffirm and continue following the medical advice all existing country travel bans," Mr Hunt said.

Earlier this week the World Health Organisation declared COVID-19 a pandemic and called on countries to take "urgent and aggressive" action to stop the spread of the virus.

The number of confirmed cases in Australia has continued to rise. As well as the first diagnosed case in the ACT and a person who attended Golden Plains music festival in Victoria, Hollywood actor Tom Hanks and his wife have also tested positive for the virus on the Gold Coast.

In a bid to soften the inevitable economic impact of the outbreak, the Federal Government also announced a $17.6 billion stimulus package which would include a one-off cash payments of $750 for more than 6 million welfare recipients, tax relief for small businesses and money to help keep apprentices in work.

The virus continues to wreak havoc on the Australian share market with the ASX plunging nearly 8 per cent after the US travel ban announcement.