A secretive farewell party has been thrown for Winston Peters tonight.

The leader of New Zealand First and former Foreign Affairs Minister has been in politics for two decades and counting.

No media were allowed in to the Parliament event tonight - except for Newstalk ZB and the New Zealand Herald.

Political Editor Barry Soper says when he suggested the idea of a party after the election, Peters wouldn't have a bar of it.

However, Prime Minister Jacinda Ardern - who Peters picked to form a coalition with over National in 2017 - convinced him to return. 

Ardern paid personal tribute to Peters, saying he had been by her side during tough times.

"I always remember the day after the terror attack in Christchurch when we travelled to Christchurch together," she told a reception including the diplomatic corp, senior officials of the Minister of Foreign Affairs and Trade and MPs.

"You were by my side that day and I don't under-estimate 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".

Peters - who's New Zealand First Party was dumped out of Parliament at the October general election - dabbed his eye several times during the tribute.

"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 stood firm on the notion of career diplomats taking postings offshore and I respect the position you took on that and I think MFAT has too.

"You worked hard to restored 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 in 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 corp 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."

He said he wanted to wish new Foreign Minister Nanaia Mahuta and associate minister Su'a William Sio the best in their tenures.

"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."

LISTEN ABOVE