All travellers from the UK or the US will need to return a negative COVID-19 test result before departing to New Zealand, the Government has confirmed.
The new testing rules will come into effect for all flights from January 15, it was confirmed on Sunday.
All travellers from the US and UK will be required to have a written form - certified by a laboratory or another form of approved evidence - showing a negative result in the 72 hours prior to departure.
Even with the negative test result, travellers from the UK and the US will still have to go through New Zealand's 14-day quarantine regime.
COVID-19 Response Minister Chris Hipkins said a "very limited" number of people may be exempt from the new requirement.
"A very limited number of people may be exempt, including if they have a medical certificate verifying they have been examined within 72 hours prior to their departure, but are unable to undertake a test for medical reasons and do not exhibit symptoms of COVID-19."
Hipkins said work is also underway to extend the requirement to other long haul flights to New Zealand.
The pre-departure test is an additional requirement to the new rule that came into force last Friday, requiring all arrivals from the UK or the US to undergo an additional test, either at the airport or on their first day of isolation.
"It reduces the risk of infected passengers on international long haul flights infecting other passengers with COVID-19," Hipkins said.
"We know this will add to the stress of travellers wanting to get to New Zealand and have made this decision carefully. It will provide further assurance for New Zealanders at a time when infections from the virus appears to be accelerating overseas.
"The managed isolation and quarantine system remains the bedrock of our border security. The new step is a further precaution to support our goal of making summer unstoppable and is consistent with the overall elimination strategy."
Pre-departure testing is intended to have an added benefit of encouraging extra-cautious behaviour before people fly and during flights and layovers - helping to minimise exposure to the virus, the Government says.
Arriving in New Zealand via the air border without evidence of a negative test will be an infringement offence, with enforcement managed by an amendment to New Zealand's Air Border Order.
The Government is developing a detailed plan with airlines to implement the new requirement. The plan will be widely communicated in time for January 15 via the Immigration NZ website and contact centre, the SafeTravel website and communications directly to airlines so they can contact booked travellers.
It comes after Japan and China have currently stopped all flights from the UK. The New Zealand Government expects to provide more details within the next week.