Australia may expand its humanitarian migration intake to accept more Afghan refugees fleeing the Taliban, after criticism it was doing too little to help vulnerable populations and had moved too slowly to rescue Afghans who had served Australian military and diplomatic missions.

So far, Australia has reserved 3,000 places within its existing humanitarian intake of 13,750 places for Afghan nationals fleeing conflict in that country.

But the prime minister, Scott Morrison, said on Thursday the 3,000 figure was “a floor, not a ceiling” and “we think we can achieve more”.

“If the overall program has to be expanded, it will be,” Morrison told reporters in Canberra. He said Afghan nationals would also have “a strong presence” in the humanitarian program in years to come.

Morrison has previously conceded Australia would not be able to rescue all of the interpreters and guards who served Australian missions in Afghanistan, or others with connections to Australia, after the rapid fall of Kabul to the Taliban.

The government had not previously ruled out taking more than 3,000 Afghan nationals in the humanitarian program, although Morrison’s latest comments contrast sharply with Peter Dutton’s tone on Wednesday, when the defence minister questioned whether other countries pledging large intakes of refugees would live up to their promises.

Speaking after a roundtable meeting with Afghan community leaders on Thursday, the immigration minister, Alex Hawke, said Australia would reserve the 3,000 non-additional places “as an initial number”.

“We are [resettling] 3,000 as an initial number. We know that will actually be larger … we are announcing what we can do, we’re announcing what we think the immediate demand is,” Hawke told the ABC.

In 2015, as the Syrian civil war sent millions fleeing over that country’s borders, Tony Abbott’s government committed an additional 12,000 humanitarian places for people displaced by conflict in Syria and Iraq.

Australia has set a figure of 13,750 humanitarian visas for this financial year. The previous annual number of 18,750 was cut by 5,000 in last year’s budget, with the government citing the impact of Covid.

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But even the 13,750 figure is unlikely to be met because Covid travel limitations are particularly restrictive on humanitarian visa holders, who do not receive a blanket exemption to travel to Australia. It has been estimated about 7,000 humanitarian visas remained unallocated last financial year.

After Australia launched its first evacuation mission out of Kabul on Wednesday, with 26 passengers on board, the government announced that 76 Australian citizens, Afghans and other foreign nationals flew out of the Afghan capital on a British plane.

Some Australians, and holders of Australian visas, have managed to board flights run by other countries, such as the UK, out of Afghanistan.

In Australia, a petition to the government urging Australia to accept an additional 20,000 humanitarian places for Afghan nationals has attracted more than 100,000 signatures, arguing Australia “has a moral duty toward the Afghan people and should not abandon them”.

That figure would match the commitment of the UK, which has offered 20,000 additional humanitarian places over five years to Afghan nationals endangered by the Taliban’s return to power. Canada has also offered 20,000 resettlement places, but these, like Australia’s commitment, are from within existing quotas.

“The forceful takeover of Afghanistan has also instilled fear and insecurity impacting all Afghans,” the petition to the government says.

It argues there are fears for numerous groups inside Afghanistan, including ethnic and religious minorities, locally engaged employees of western embassies and military forces, human rights activists, employees working in Australian government-funded schools and NGOs, Australian-educated Afghans, LGBTIQ+ Afghans, artists, journalists and others.

“After almost two decades of intervention and promises to the Afghan people, promises of protection for persecuted groups, women, democratic freedoms and rule of law, prime minister Scott Morrison has a moral obligation to act in response to the humanitarian crisis in Afghanistan,” the petition says.

Sajjad Askary from the Asia Pacific Refugee Rights Network said the persecuted Hazara ethnic and religious minority would be targets of the Taliban.

“In the 1990s, thousands of Hazara were massacred in a number of days. The Hazara are now at risk once again – as potential victims of genocide.

“The Australian government can and must act now and grant humanitarian visas to all those in Afghanistan who face violence, persecution and potential genocide.”

Sarah Dale, the principal solicitor at the Refugee Advice and Casework Service, said the government could immediately commit to 20,000 additional humanitarian places for Afghans, as a “reasonable and proportionate and achievable” initial response.

“Australia could easily and sustainably support that community and give those people safety.”

But she said the government could also assist Afghans already in Australia, by giving those on temporary visas permanent protection, and by resettling their family members from Afghanistan.

“The government promised to protect the vulnerable people of Afghanistan. There are thousands here in Australia asking for that protection, thousands more of their family members in Afghanistan who need it. Those are two steps that the government could take tomorrow.”

There are currently 4,247 Afghan refugees who have temporary protection in Australia.

The Catholics for refugees alliance has urged the government to offer sanctuary to a far greater number of Afghans.

“We are grateful that the government is taking action, even if it’s too little, too late”, Jan Barnett, Josephite Justice Network coordinator, said. “Malcolm Fraser was able to bring in tens of thousands Vietnamese without internal conflict. Even Tony Abbott was able to bring in 12,000 Syrians and Iraqis with the stroke of a pen. Surely prime minister Morrison can do better than 3,000.”

Human Rights Watch has written to the prime minister arguing that anybody “perceived as being associated with Australia” is potentially at risk of Taliban persecution, and urged Australia to broaden its assistance to Afghans beyond evacuation flights from the capital.

“Many in need of assistance are not at the Kabul airport, but may have already left the country, or are in the process of doing so, and may require documents and assistance in third countries.”