It could cost up to $14 million to get New Zealanders stranded overseas because of Covid-19 home from high-risk countries, according to just-released documents.
And because the government expects there could be demand from several thousand New Zealanders for mercy flights - and with limited resources, it has had to come up with a priority list of countries.
That priority list, drawn up by the Ministry of Foreign Affairs, is detailed in a paper from Foreign Minister Winston Peters' office, dated 15 April.
However, the full list of countries has been withheld.
The Ministry of Foreign Affairs said that based on registrations on the Safe Travel website, there were 3326 New Zealanders in high-risk countries and 7623 in moderate-risk countries and 11,850 in low-risk countries.
It was unclear how many of them were stranded travellers.
"It is beyond our resources to bring all New Zealanders home and there is an urgent need for clarity over where we will concentrate our efforts and where we will not," the paper said.
"Orchestrated charter options from low-risk countries also undermine efforts by commercial carriers to sustain routes which are important to New Zealand broader economic activity."
The cost to repatriate those in higher-risk countries could be as much as $14 million, the paper said.
As well as flights organised by the New Zealand government, it could also work with other countries to get people home, as has already happened in a number of cases.
The paper also said there should be a clear signal to those in low-risk countries that the government would not be organising repatriation flights and that they should use commercial flights, while they were still available.
"This will give stranded New Zealanders as much time as possible to explore other travel options or to make better arrangements to shelter in place," the paper said.
"Failure to be clear on this could be offering perverse incentives. There is anecdotal evidence that New Zealanders in Europe are holding off using commercial air options because the ticket price is higher than normal and they are waiting to see if repatriation is offered or whether they can take advantage of evacuation flights being chartered by European governments to get their nationals home from New Zealand."
The paper also sets out the rationale for the cost per passenger of government-assisted charter flights.
People are being charged a flat fee, depending on the flight duration: $1500 for up to four hours, $3500 for 4 to 14 hours, and $5500 for over 14 hours.
By mid-April, the government had already spent more than $2.2 million helping 300 people return to New Zealand on both government-assisted charter flights, flights with partners such as Australia, and commercial flights.
Countries people returned from included: China, Peru, Uruguay, the United States, Japan and Nepal.
Those figures excluded the more recent charter flights from India.
Where the government has helped to subsidise the flight, the average per passenger repatriation subsidy is approximately $12,500, the paper said.