Passengers boarding flights after midnight tonight won't be allowed to get on unless they have a voucher or have been granted an exemption.
A Managed Isolation and Quarantine spokesperson said the reality was that there were a limited number of rooms available in New Zealand.
"We currently have a short-term spike in arrival numbers from 1-12 November, and 23 November-12 December.
"The Managed Isolation Allocation System (MIAS) is now fully booked during this period, which means there is no capacity for additional bookings in managed isolation facilities."
As for Kiwis who might need to return home for a funeral over the festive period, it was also unlikely they would be allowed as there were "very restrictive emergency allocation criteria".
"This is a last-resort option and the threshold is extremely high. We expect that very few approvals would be granted, and it is important to note that people still need to complete their 14 days managed isolation.
"Because of Covid, this Christmas is very different to the last. We're asking people to be flexible and if there are no available places in managed isolation on their preferred date, to check and see if there are any places available on another nearby date."
The new voucher system not only provided advanced notice of who was arriving into the country, but also allowed its facilities to be better prepared to support any additional needs they might have.
More than 65,000 people had flown back into the country and completed their managed isolation over the past six months.
The voucher system would streamline the current process, while helping provide a better experience for travellers at their facility.
People who had already booked their return flights home prior to the law coming into effect would also still need a voucher.
