Aotearoa and the United Kingdom have agreed the principles of a $1 billion free-trade agreement, which includes protections for cultural taonga including the Ka Mate haka.
The deal, expected to come into force next year, will eliminate 97 percent of tariffs of Aotearoa exports to the United Kingdom, which is expected to save NZ exporters $40 million a year.
In a video conference between the two leaders UK Prime Minister Boris Johnson said the deal was ‘a big moment’ praising the closer ties, Mānuka honey and Aotearoa's Sauvignon Blanc.
He used a rugby analogy to describe negotiations.
"We've scrummed down, we've packed tight, and together we got the ball over the line and we have a deal," Johnson said.
And Ardern added, "unlike a rugby match, we can both come off the field feeling like winners on this occasion".
The agreement says the UK will work with Aotearoa to "advance recognition and protection" of cultural artefacts like the haka.
The UK will also formally acknowledge Ngāti Toa Rangatira's guardianship of the Ka Mate haka in a separate document.
Last year British nurses had to apologise for performing a haka condemned as "offensive and degrading".
British businesses have also been condemned for using haka to sell beer and carpets in the past.
The agreement is only the second such trade deal to be struck since the UK left the European Union last year and inked an agreement with Australia.
Trade Minister Damien O'Connor says Aotearoa exports will rise by up to 40 percent under the agreement.
Both the UK and NZ governments say they are working to extend immigration rights for Kiwis keen to work in the UK and vice versa.