SYDNEY (REUTERS) - Australian Prime Minister Scott Morrison on Friday (March 27) tightened enforcement on self isolation for thousands of citizens returning from overseas, saying states and territories would quarantine all arrivals in hotels.

The Australian Defence Force would also be deployed to help enforce the self-isolation rules, Mr Morrison said.

Earlier, Foreign minister Marise Payne said Australia will also charter commercial flights to bring home hundreds of its citizens stranded in South America.

"We have agreed to consider, on a case-by-case basis, supporting commercial airlines to operate non-scheduled services to less central locations for Australians," Ms Payne said.

"We continue to urge Australians who have opportunities to travel back to Australia by commercial means, to do so as soon as possible."

The number of coronavirus cases in Australia surpassed 3,000 on Friday from less than 100 at the start of March, according to health authorities, raising fears about a wider spread in the community.

The country has reported 13 deaths from the pandemic so far.

Although well below levels elsewhere in the world, the pace of Australia's infections is picking up speed, raising fears the country's hospitals will soon be overwhelmed.

"The one figure that we are most worried about is the number of people that are getting it within the community," said New South Wales (NSW) state premier Gladys Berejiklian.

"When you have cases that come from overseas, you can monitor them and you have a source. But when it is community to community transmission and you don't have a source, that means the virus is starting to spread in the community without us knowing where and that's a concern."

To prevent the spread of the virus within the state, NSW has tightened restrictions on people movement and is enforcing self isolation rules. But Ms Berejiklian has warned further mobility restrictions were on the cards.

NSW state, of which Sydney is the capital, recorded a jump of 186 Covid-19 cases overnight, taking the total to 1,405.

Health authorities are particularly concerned about the 145 cases which were acquired from an "undeterminable source."