Prime Minister Scott Morrison has called on international travellers without job prospects in Australia to return to their home countries, as authorities grapple with the public health risk of backpackers crammed into share houses and underground hostels.

Mr Morrison said there were still "quite a number of people" who remained in the country on visitor visas and that it was time for them to "make your way home".

Scott Morrison says international visitors without means to support themselves should return home. Credit:Alex Ellinghausen

"At this time, Australia must focus on its citizens and its residents to ensure we can maximise the economic supports that we have," the Prime Minister told reporters in Canberra on Friday.

There are up to 1.6 million temporary visa holders in Australia who are not eligible for social security benefits and face a narrowing window of opportunity to secure a flight home.