Jealous at the victory of Australia in the 2012 Eurovision Song Contest (in which they were included as a one-off, but quite literally stole the show), New Zealand immediately set about one-upping their trans-Tasman rivals, and applied to join the European Union. Brussels made the process very easy for them, as NZ was basically solvent and would improve some of the continental stats.
Although disappointed to hear that there was no way of 'winning' the EU, John Key pressed ahead with the project, and New Zealand joined after a referendum that November, and had an interstitial EU Parliament election along with the local elections in the winter of 2013. Aotearoa was awarded 13 seats, one of which was reserved for the Maori roll - although the Germans muttered darkly about Apartheid, to which the British responded "sorry, no, I didn't sneeze, so, er?".
The first regular European elections to which New Zealand was privy came the following year, in 2014. Although there were parliamentary elections scheduled for later that year, no effort was made to combine the two - a decision which reduced the turnout in both polls and, it is claimed, helped National cross the line to a majority in the domestic election. John Key refused to comment on the tactics of this.
Key's other tactic was to submit a joint list with their small support partners - vote-splitting from ACT had denied National a seventh seat in the general roll constituency in 2013, so they were brought onside by the gift of the second spot on the joint list. This seat was filled by Jamie Whyte, who remains the party leader. However, the National Coalition actually lost two seats overall, partly due to the rise of the right-wing Christians in the Conservative Party, and partly because of the growth of NZ First as a home for Eurosceptic voters.
The Conservatives won a single seat, which went to party leader Colin Craig - he was ousted as leader in the midst of a sexual harassment scandal shortly afterwards, but has controversially remained an Independent MEP within the Tory/PiS ECR group, with the benefit of a decent salary, better perks, and a Brussels address where he can avoid embarrassing encounters with old mates.
Winston Peters found the role he was born to play in the anti-Europe demagogue, railing against the corruption, bureaucracy and humbug of the institution, as well as the unworkability of putting open borders in place with countries with whom New Zealand shares no borders. NZ First therefore topped the poll, which led to some very tepid takes about how they were inevitably going to win the parliamentary election. They did not.
A fair proportion of the NZ First gains came from Labour, which lost them their third MEP - however, this loss was offset by their victory over the Maori Party's Marama Fox in the Maori Roll constituency.
In the 2020 coalition agreement between Labour and NZ First, it was agreed that New Zealand should trigger Article 50 as soon as possible - a policy that enjoys almost unanimous support in NZ now that John Key's electoral magic has worn off and a generation of Kiwi civil servants have had a gruesome taste of the decadence of Belgian life.