Prime Minister Scott Morrison insists his government is doing everything it can to bring hundreds of Afghans who worked alongside Australian troops to safety.
Former prime minister John Howard believes Australia has a moral obligation to help the Afghan workers, especially as the Taliban advances throughout the country.
"We're doing everything we can," Mr Morrison told ABC radio on Friday.
At least 1400 Afghan workers and their families who worked with the Australian government have been granted visas in recent years.
"Hundreds are in that process right now," the prime minister said.
"We're doing that as fast and as safely as we can."
He said there was a "high level of urgency" within the government to get the job done.
"It's obviously an environment in which it is difficult to operate, people would appreciate that."
Some protection visa requests have been rejected because the Afghan workers were subcontractors, and not directly employed by the Australian government.
Mr Morrison said Afghan subcontractors could apply through Australia's humanitarian visa stream, rather than one dedicated to locally engaged workers.
"We work through both channels," he said.
Foreign Minister Marise Payne said Australia would not leave any eligible Afghans behind.
"We're not going to leave behind anyone who worked for us and who is properly eligible," Senator Payne said.
Pressed specifically about subcontractors, she said humanitarian visas were open to all Afghans who felt under threat from Taliban.
Labor accused the minister of being "tricky" in her language, saying the Taliban did not distinguish between contractors and directly employed staff.
Mr Howard, who sent Australians to fight and die in Afghanistan, doesn't want the subcontracted locals they fought alongside left behind to meet the same fate.
He has piled pressure on the federal government to grant protection visas for Afghan interpreters, contractors and security guards who fear for their lives under resurgent Taliban rule.
"It was a moral obligation that we shamefully disregarded many years ago when we pulled out of Vietnam," Mr Howard told SBS News.
"I do not want to see a repetition of that failure in relation to Afghanistan."
Mr Howard, who doesn't regret following the US to war in Afghanistan, said the subcontractor technicality should not be used to keep those in danger from safety.
"I don't think it's something that should turn on some narrow legalism," he said.
"If a group of people gave help to Australians such that their lives and that of those immediately around them are in danger we have a moral obligation to help them."
Taliban fighters have been advancing across the country in recent weeks as Australia and the United States end two decades of involvement in Afghanistan.
Australia has granted more than 230 visas to Afghans workers and their family members since April 15.