Prime Minister Jacinda Ardern has defended having an Air Force Boeing 757 fly back from Nauru after dropping off Foreign Affairs Minister Winston Peters to collect her and deliver her to the Pacific Islands Forum on the island for one day.
The round trip comes at a cost of $80,000 on fuel alone.
While Peters and a contingent flew to Nauru yesterday, about five-and-a-half hours from New Zealand, Ardern will go on Wednesday for the leaders' retreat.
The Prime Minister is still breastfeeding her 11-week-old daughter Neve, who does not have immunity to visit an environment such as that on Nauru.
"I spent quite a lot of time deliberating over whether or not I would attend the Pacific Islands Forum in Nauru. I analysed all of my options," Ardern told reporters yesterday.
Ardern made a decision that she would fly to Nauru early on Wednesday, necessitating the return of the 757 to New Zealand to pick her up instead of flying one hour on to the Marshall Islands to await the return flight on Wednesday.
There is no room on the island of Nauru for all the planes that will be bringing Pacific ministers and leaders together for the three-day forum so the planes go on to the Marshall Islands to wait.
"The other option was for me not attend at all but, given the importance that we place on the relationships with the Pacific Islands in the reset, that equally didn't feel like an option.
"When weighing up the logistics I asked officials to check the extra costs I would be imposing on the Crown if I were travelling separately. On balance I decided it was worth me travelling for the full day on the Wednesday to fulfil my obligations as Prime Minister."
Ardern said it was a unique situation and she did not expect it would happen again.
Asked whether she thought the cost was a good use of taxpayer money, Ardern said she asked officials and was told the 757 had to leave Nauru, and that it needed to clock up a certain number of flying hours anyway.
"I never had anything that suggested to me that it was such a significant spend that that was of concern."
Ardern said she would be raising the issue of refugees and asylum-seekers in detention on Nauru while she was there and still hoped to visit people in detention centres.
Peters and officials were scoping possible opportunities for that.
In 2011 Labour was critical of a decision by then Foreign Affairs Minister Murray McCully after he used Air Force aircraft to fly to Vanuatu and back, collecting other government ministers in Samoa, at a cost of $61,000.
"Being flown around in your own aircraft is a 'nice to have' but in these tough times the cost to taxpayers is vastly more than a commercial flight," Labour MP David Shearer said at the time.