Acting Foreign Affairs Minister Simon Birmingham announced the plan on Saturday to get more Australians home on flights running between January 31 and March 31.

He told Sydney's 2GB radio on Sunday the actual number of passengers will depend on the quarantine arrangements at the time.

Special arrangements are in place for the Northern Territory, the ACT and Tasmania to activate additional sites for quarantine that can take those people on the 20 flights.

The decision for the chartered flights came after the Emirates airline withdrew services to the east coast, coinciding with Australia's national cabinet agreeing to reduce the cap on returning overseas travellers due to quarantine restraints in NSW, Queensland and Western Australia.

"But the capacity that Emirates had under that cap will be reallocated to the other airlines, to Qatar, to Singapore, to others who are still flying," Senator Birmingham said.

"And importantly, these 20 facilitated flights the government will undertake will come in over and above the cap."

Senator Birmingham, who is also the finance minster, expects travellers on the government flights will be making a contribution for their travel.

"It doesn't cover the full cost of the flights, but we do expect people to make essentially a contribution into buying an airline ticket," he said.

"Obviously, there are some circumstances where we may recognise an exceptional case of difficulty or hardship or otherwise. We have already distributed some $15 million in hardship payments to vulnerable Australians overseas."

Seats will be given as a priority where possible to people who are in special need.

"So clearly, those parts of the world where there are larger numbers of Australians, where it is difficult in terms of the COVID situation present are the ones that historically we've seen a lot of these facilitated flights come from," he said.

"So the UK, occasionally parts of Europe, India, and I would expect that there would still be a good number of them from similar countries."

There are some 37,000 Australians registered with the Department of Foreign Affairs and Trade who want to return home.

Australian Associated Press