The number of Australians trying to return home has continued to rise with 34,000 people now stranded overseas.
New figures provided to Senate estimates on Wednesday represent a rise of about 2000 since last week, with concerns some vulnerable people won't be home for Christmas.
Department of Foreign Affairs and Trade senior official Fiona Webster said there were complex issues with some people in remote parts of the world.
"We're very hopeful we could bring a very good number home before Christmas," she told the hearing.
Labor Senator Penny Wong accused the government of blaming some Australians for not returning home at the onset of the coronavirus pandemic.
"We all know what happened to the commercial aviation market. There were not many opportunities for people to return home," she said.
"There were people who were desperate to come home through that period who did not have the opportunity to return."
In July, Prime Minister Scott Morrison said there had been many opportunities for people to return.
Foreign Minister Marise Payne denied the prime minister had apportioned blame, pointing to 351,000 people that returned between March and July.
More than 400,000 Australians have returned home since the start of the pandemic in March.
The government has helped 30,000 of those to come home on 357 flights, including 10,000 people on 66 flights facilitated by the Department of Foreign Affairs and Trade.
Two special flights from London and New Delhi carrying 344 people landed in Darwin earlier in the week.
DFAT secretary Frances Adamson told Senate estimates on Wednesday more work was being done to lift quarantine caps.
"Our response has sometimes fallen short but I am extremely proud of our overseas network and the department as a whole," she said.
"Our top priority continues to be helping Australians overseas in what is the largest consular operation in our history."
Officials were also quizzed about more than 3000 people stranded abroad having their personal email addresses shared with strangers in three privacy breaches over two months.
"It was a matter of deep disappointment it happened again," Ms Adamson said.
"We've got a lot of staff who are working very hard, who are tired and who regrettably have made mistakes."
The committee heard a technical fix had been put in place to ensure email addresses would not be shared again.
Australian Associated Press