Prime Minister Jacinda Ardern says the Government is "very concerned" by the situation in Afghanistan.

Ardern is speaking at her post-Cabinet press conference following the Taliban seizure of the Afghan capital Kabul overnight.

Defence Minister Peeni Henare and Chief of Defence Air Marshal Kevin Short are also at this afternoon's press briefing.

There were 53 New Zealanders in Afghanistan and all had been offered consular support, Ardern said.

Today Cabinet had considered support for those New Zealanders stuck there, assisting those Afghanis who had supported New Zealand during the conflict, and how New Zealand could assist with the humanitarian response.

Cabinet discussed the plight of the 30-odd Kiwis and their families in Afghanistan, as well as the group of 38 locals who helped the NZ Defence Force in Bamyan in a variety of roles including as interpreters, electricians and mechanics.

They have fled their villages and towns in recent weeks, either for remote, mountainous safe havens, or Kabul, where they hoped they might be safe as they renewed pleas with the New Zealand Government to review their immigration cases.

Although New Zealand has resettled 44 former Afghan interpreters and employees, along with 96 immediate family members since 2012-13, many others have had immigration applications declined in recent months.

'Awful situation in front of us'

Act party leader David Seymour asked this morning why their applications had been rejected.

"The Taliban have moved fast but this Government had opportunities to help much sooner than today," Seymour said.

"Canada got the Afghan people who helped them out last month."

National MP and former Defence Minister Gerry Brownlee wouldn't say whether the Government had dropped the ball.

"You can go through that endlessly. The reality is we've got a very, very awful situation in front of us at the moment. The focus needs to be on what should be done, and done quickly.

Smoke rises after fighting between the Taliban and Afghan security personnel in Kandahar, south-west of Kabul, Afghanistan, on August 12. Photo / AP

"Anyone who's associated with or been part of any resistance to the Taliban will be definitely in danger. We know what will happen to those people [if caught]. They will be subjected to very rough treatment, and at the end of it, lose their life."

The Green Party said it was "heartbreaking" to know that Afghans face the prospect of living under Taliban rule once again, with women and girls at the greatest risk of sexual and gender-based violence.

The party's human rights spokesperson Golriz Ghahraman said New Zealand could work with allies and partners to ensure Taliban fighters have no more funding and resources, even if that means standing up to our trading partners.

Brownlee joined Ghahraman in saying that the Western efforts in Afghanistan had failed.

"The consequences of that could well be that Afghanistan becomes a home again for the sort of terrorist activity that threatens anybody, anytime," Brownlee said.

"They will become a rogue state if the rest of the world doesn't engage with them in on some level."

That didn't mean accepting "the philosophy of that regime".

"But we have to accept the reality of there being that regime. Their history is not one of compromise, nor generosity to people who've been opposed to them in the past.

"But you would hope that as they reassume control of the country, they might want to be more engaged with the international community so they can achieve some of the things they claim they're able to deliver for the Afghan people."

Vaccine rollout

On the vaccination rollout, the Prime Minister said last week was the biggest yet, with nearly 300,000 people getting a vaccine.