"I always remember the day after the terror attack in Christchurch when we travelled to Christchurch together," she told a reception including the diplomatic corps, senior officials of the Minister of Foreign Affairs and Trade and MPs.
"You were by my side that day and I don't underestimate the value and importance … I placed on having your wisdom and your support on that darkest of days.
"But you took that strength with you into the region. You recognised that it was important that immediately we work alongside our Muslim neighbours to make sure that they understood the strong stance that we would take against what happened on our shores."
He had immediately travelled to Indonesia, Turkey and Malaysia to engage with counterparts in the Islamic world "to tell our story, to make sure we kept that relationship of trust and understanding".
"You will leave a legacy that we are very proud of and it is my pleasure to be here today to say the simple words, thank you.'"
Referring to him as "Mr Peters" throughout, she specially mentioned the Pacific Reset, which increased New Zealand's focus on the Pacific.
"The Pacific Reset became the hallmark of our term in office from a foreign affairs perspective and you were the architect of it."
Ardern recounted their first trip together on a Pacific mission during which time she had seen first-hand his love and appreciation for the region and relationships he had built.
She also said she respected Peters for his policy of preventing political appointments in diplomatic posts – with the exception of former Labour deputy leader Dame Annette King who is High Commissioner to Australia.
"You had an absolute vision that you would restore diplomatic capability, that you would restore the notion of offshore postings to career diplomats.
"You worked hard to restore our relationships with traditional friends in the Commonwealth, to build our relationships with like-minded friends including in North America, a tangible example of which is the Kiwi Act."
Peters thanked her for the tribute and said he was overcome.
He did not say anything about the election loss or about what his plans were.
He paid tribute to diplomats, saying the diplomatic corps was the "most special bureaucracy worldwide".
"There is no demur. There cannot be any argument about that. They sit above in every other nation, the layers of excellence – and bureaucracy can be good when it is organised and run properly by the right men and women or, dare I say it, the right women and men."
What had underpinned New Zealand's foreign policy was consistency and continuity, Peters said.
"Both are pursued with great professional skill by the Ministry of Foreign Affairs and Trade.
"Consistency and continuity of New Zealand's foreign policy is also strengthened by those objectives overwhelmingly transcending party interests: country first, party second, that is the New Zealand way."
"Know there are people inside and outside the building whose experiences are available to you should you ever require it.
"It has been a personal privilege to twice serve as Foreign Minister and over a 15-year span, and sharpening our policy focus on our neighbourhood the Pacific has assumed ever greater strategic importance.
"The blue continent is a special place," he said.
"It has hitherto not been conquered. It has hitherto been seen to be too big. There have been three failed attempts over the past 250 years but the Pacific still stands free for its diverse peoples. But future historical pressures should not be taken for granted.
"Pacific challenges are multi-faceted and they run deep."
He made a special mention of Japan and Indonesia's interest in the Pacific and said that would be of benefit to New Zealand.
It had been a privilege to be Foreign Minister but also a lot of fun.
"Sadly there are so many cities that you leave, having never seen them, arriving in the morning climbing off the plane, having a shower, getting into a new suit and going straight to the meetings but we are so far away from many parts of the world, that has been part of the job for many foreign ministers. But it has been fun."
Peters said what worked for him were some plain fundamentals: "Being intellectually curious about history and other cultures helps understanding; having a good office with smart people to challenge your thinking seriously helps decision-making; and knowing that New Zealand's diplomatic and national values and the foreign policy that project them to the outside world are the rock upon which you stand."
