The Defence Force already has four personnel on the ground in Afghanistan's capital Kabul, who will help to establish a New Zealand presence at the airport and begin evacuations.
Prime Minister Jacinda Ardern announced plans on Monday to send a C-130 Defence Force plane to the Middle East to bring back an estimated 53 Kiwis and 37 Afghan nationals who have assisted New Zealand, along with their families.
It came after the Taliban, which ruled Afghanistan from 1996-2001 and was accused of aiding Al-Qaeda, captured the capital Kabul, forcing thousands of Afghans to flee to the airport in harrowing scenes, desperate to be evacuated.
The C-130 Hercules took off from Auckland on Thursday, and according to Commander Joint Forces New Zealand Rear Admiral Jim Gilmour, it should now be somewhere between Australia and a stopoff point across the Indian Ocean.
"The aircraft itself has some cargo onboard, the crew, some maintenance people and 16 passengers. We've had more people head towards the region via civilian last night and there will be another group tomorrow," he told The AM Show on Friday.
"The breakdown of people we're including in this operation covers the air crew, maintenance, air load teams, we've got a medical team to support our people and the evacuees, and we've got a force protection cell as well.
"We're obviously interested in protecting the aircraft while it's on the ground but we also have a responsibility to protect it whilst it's in flight, and we also have a requirement for our footprint inside Kabul to have adequate protection around it.
"They will be armed whilst on the ground in Kabul."
Defence Minister Peeni Henare said due to the developing situation, up to 80 personnel are being deployed - double the number he said would be sent when the mission was announced on Monday.
"We will be working alongside partner militaries, such as our ally Australia, as we respond to this rapidly evolving humanitarian situation," Henare said on Thursday.
"This means that we may see some individuals bound for New Zealand, returned on Australian/partner's assets, and vice versa, as partners look to cooperate wherever they can to safely expedite the evacuation."
How will the Defence Force get into Kabul?
Rear Admiral Jim Gilmour told The AM Show partner militaries have facilitated New Zealand Defence Force personnel getting into Kabul.
"I'm pleased to note that the security situation inside the airport is improving, although it's still chaotic outside," he said.
"One of the key things we need to establish first is New Zealand representation at that airport so we can start facilitating and planning to receive evacuees and get them out of the country."
Gilmour said he's aware that some New Zealand passport holders have been turned away at the airport's security perimeter, which is why it's important for officials to have a presence there in order to start receiving eligible people to bring back.
"Once we establish that eligibility, we can literally get a list of those who will be travelling with us and keep them in a safe area inside the airport.
"Our people are totally aware that it's been a traumatic event for all of those who will be travelling with us and we need to set up a situation that's secure inside Kabul Airport, where they can be cared for, feel safe, and then we'll pull the aircraft forward into the country to get them out."
Gilmour doesn't expect it to be one flight.
"I'm expecting that we'll continue flying in and out of Kabul until we've got every approved foreign national and approved traveller to a place of safety."
He's expecting to bring back hundreds of foreign nationals. By comparison, the UK announced it will take up to 20,000 people looking to exit Afghanistan, with 5000 due to be accepted in the next 12 months.
Australia's first evacuation mission to Afghanistan rescued just 26 people, but Prime Minister Scott Morrison says he hopes it will ramp up, with a promise to resettle about 3000 Afghan nationals.
The Defence Force personnel will also be monitoring other threats.
"We're aware that it's a deteriorating situation out there so the things that we track are the security of the runway, security of the airport itself," Gilmour said.
"We're also paying attention to threats from other actors like ISIS and the throng of people desperately trying to get into the airport. We watch those very carefully.
"The aircraft won't be getting airborne towards Afghanistan until we are confident that the security situation on the ground is adequate to receive the aircraft safely."
All deployed Defence Force personnel are vaccinated and will be carrying out COVID-19 prevention protocols. They will complete 14 days of managed isolation on their return to New Zealand.