The Prime Minister meanwhile remains confident that he'll keep his promise, made in September, to get those waiting Australians home for Christmas, and won't budge on blocking the ACT's desire to allow some seats to go to international students.

Senior figures from the Department of Foreign Affairs and Trade, among other relevant agencies, appeared before a parliamentary committee on Thursday to answer questions about the scale of Australians wanting to be repatriated from overseas brought on by the COVID-19 pandemic.

DFAT deputy secretary Tony Sheehan said in his opening speech the number of Australians on his list now totalled 36,875 with 8070 of those being listed as vulnerable.

The number marks a rise from figures provided by Prime Minister Scott Morrison on September 18 when it was confirmed around 24,000 were hoping to return with about 4000 vulnerable Australians among them. Mr Morrison said he was hoping to bring as many, "if not all", of them home as possible before Christmas.

Since September, DFAT confirmed 14,000 registered with the department had returned home but the list was growing as circumstances abroad continued to change for the worse.

For those Australians hoping to arrive in the country for Christmas, a December 11 deadline is looming to allow for the mandatory two-week quarantine to take place.

Mr Sheehan would not provide the number of repatriation flights planned, apart from the two announced, but said there would be "several" before December 25.

Infrastructure deputy secretary Christine Dacey said there were around 29,000 flight seats available between Thursday and Christmas, across more than a hundred flights but availability was subject to quarantine cap restraints.

"[There are] roughly 29,000 seats coming into the country on regularly commercially scheduled flights and there are about 30,000 empty seats a week because of the quarantine capacity issue," Ms Dacey told the committee.

The hearing had earlier heard from Australians about their experience waiting for repatriation. One, named Carly who asked for her surname not to be made public, said she sent several hundred emails and made multiple phone calls to DFAT officials and politicians asking for help. "I literally never heard back."

Another family, David and Kate Jeffries and their son Mitchell, moved to Canada to care for a family member who had been diagnosed with cancer. Their return flights in March were cancelled and they have been trying to get home ever since. They estimate their additional costs due to the uncertainty of repatriation is more than $50,000, and said they felt betrayed by the broken promises of airlines and their government.

"The reality is there is no queue that our family can join and reserve our spot in hotel quarantine," David Jeffries said. "Race horses, tennis and cricket players, unskilled labourers, they're given places in front of people trying to return home."

Fiona Wright was one of the lucky Australians to get on a repatriation flight from India. She told the hearing it was a mystery to those waiting how DFAT chose among them.

Labor senator Kristina Keneally told Sky News on Thursday news of former finance minister Mathias Cormann's taxpayer-funded private flights around Europe in a bid for a role as head of the OECD flew in the face of Australians still waiting for a flight home.

"If we can send a military plane to shoot Mathias Cormann around the globe, so that he can apply for a new job, surely we can send out military planes to bring our fellow Australians home," Senator Keneally said.

"What kind of government is this - it has one rule for them and their mates and another rule for everyone else that just leaves stranded Australians behind."

Senator Keneally calls for a federal quarantine facility to be set up, "so that we can get these people home, through quarantine, and back to their families by Christmas".

Mr Morrison said on Thursday he thought they'd been making good progress on his promise.

"When I made the statement I was making reference to the 26,800 ... registered at that time, thinking to come home," Mr Morrison said.

"About 35,000 have arrived back in Australia by now, and there will be more who arrived home in Australia by the end of the year."

Securing travel for more Australians will depend on the available quarantine capacity, he noted. Caps on arrivals were a call from state governments to limit risk of transmission of the virus into Australia.

"We understand that," he said. "I appreciate particularly New South Wales, who have carried the lion's share of the load of people coming back to Australia ... Victoria would take more but they are coming back into the process gently to ensure that the quarantine systems are not breached."

The ACT government, along with some of the states, have requested that international students be included in the limited numbers of arrivals, but the federal government is still holding firm against that.

"We simply cannot do that because the priority is to get Australians home," Mr Morrison said.

In the same media conference, Foreign Minister Marise Payne noted the ACT was among those capable of receiving travellers:

"We have a flight arriving in Canberra today which will fly from Singapore, bringing 120 passengers going into quarantine in the ACT."