Editing Prime Minister of New Zealand (section)

===Towards modern leadership===
One change brought about by the [[First World War]] was direct participation in governing the British Empire. Previously, New Zealand prime ministers had attended occasional colonial and imperial conferences, but they otherwise communicated with London through the governor (a position then appointed by the British government). In 1917, British Prime Minister [[David Lloyd George]] offered the New Zealand prime minister a seat in the [[Imperial War Cabinet]], the British Empire's wartime coordinating body. In 1919, Prime Minister William Massey signed the [[Treaty of Versailles]] on behalf of New Zealand, signalling the [[independence of New Zealand]] within the empire, although Massey downplayed the event as an ardent imperialist.<ref name="party leadership"/>

Constitutional conventions adopted in 1930, following the [[1930 Imperial Conference|Imperial Conference]] held that year, increased the domestic and international prestige of the prime minister. The [[Statute of Westminster 1931]] confirmed that Dominions had exclusive power to make their laws. New Zealand initially resisted greater autonomy and did not [[Statute of Westminster Adoption Act 1947|adopt the statute until 1947]]. Increasingly New Zealand began to act independently in foreign affairs. During the 1940s the prime minister's profile rose as New Zealand signed several international treaties.<ref name="party leadership"/> In 1967, [[Keith Holyoake]] became the first New Zealand prime minister to select candidates for the position of governor-general without any involvement of the British government. Holyoake advised the monarch, [[Queen Elizabeth II]], to appoint [[Arthur Porritt, Baron Porritt|Sir Arthur Porritt]], the first New Zealand-born governor-general.<ref name="governors" />

[[File:John Key Helen Clark handshake.jpg|thumb|upright=1.2|The 37th and 38th prime ministers of New Zealand, pictured in 2009: [[John Key]] with his predecessor, [[Helen Clark]].]]
After the [[mixed-member proportional]] (MMP) system was [[electoral reform in New Zealand|introduced in 1996]], prime ministers have had to manage minority governments, although the Ward government formed in 1928 and the Forbes government formed in 1930 are two earlier minority government examples.  The Forbes-led United and Reform coalition from 1931 to 1935 was the country's first coalition government outside of wartime. The skill of MMP management was exemplified by [[Helen Clark]]'s nine years as prime minister (1999–2008), when her Labour government remained in power thanks to a range of [[confidence-and-supply]] agreements with five smaller parties.<ref>{{cite encyclopedia|last1=McLean|first1=Gavin|title=Premiers and prime ministers – Towards modern leadership|url=https://teara.govt.nz/en/premiers-and-prime-ministers/page-4|encyclopedia=[[Te Ara: The Encyclopedia of New Zealand]] |access-date=16 May 2018|date=1 December 2016}}</ref>

Until the premiership of Helen Clark, it was customary for senior members of the legislature, executive and judiciary—including the prime minister—to be appointed to the [[Privy Council of the United Kingdom|British Privy Council]], granting them the style "Right Honourable". This practice was discontinued at the same time as the abolition of knighthoods and damehoods in 2000 from the [[New Zealand royal honours system]]. National's [[John Key]] became prime minister in 2008 and moved to restore titular honours,<ref>{{cite news|url=http://www.nzherald.co.nz/honoured-new-zealanders/news/article.cfm?c_id=513&objectid=10560600|title=Titles of Dames, Knights to be restored – Key|work=[[The New Zealand Herald]]|date=8 March 2009}}</ref> but did not resume appointments to the Privy Council, meaning Key was styled "The Honourable". On 3 August 2010, the Queen granted the prime minister, along with the governor-general, [[Speaker of the New Zealand House of Representatives|speaker of the House of Representatives]] and [[Chief Justice of New Zealand|chief justice]], the style "Right Honourable" upon appointment.<ref>{{cite web|url=http://www.scoop.co.nz/stories/PA1008/S00014/new-rules-for-use-of-the-right-honourable.htm|title=New rules for use of the Right Honourable|publisher=The Royal Household |via=[[Scoop.co.nz]]|date=3 August 2010}}</ref>

On 21 June 2018, Labour's [[Jacinda Ardern]] became the first prime minister of New Zealand (and second elected head of government in the world) to give birth while in office.<ref>{{cite news|url=https://www.bbc.com/news/world-asia-44568537|title=Ardern and Bhutto: Two different pregnancies in power|last=Khan|first=M Ilyas|date=21 June 2018|work=[[BBC News]] |access-date=22 June 2018|quote=Now that New Zealand's Prime Minister Jacinda Ardern has hit world headlines by becoming only the second elected head of government to give birth in office, attention has naturally been drawn to the first such leader – Pakistan's late two-time Prime Minister [[Benazir Bhutto]].}}</ref><ref>{{cite news|title=It's a girl! Jacinda Ardern gives birth to her first child|url=https://www.newshub.co.nz/home/new-zealand/2018/06/it-s-a-girl-jacinda-ardern-gives-birth-to-her-first-child.html|archive-url=https://web.archive.org/web/20180621093641/https://www.newshub.co.nz/home/new-zealand/2018/06/it-s-a-girl-jacinda-ardern-gives-birth-to-her-first-child.html|url-status=dead|archive-date=21 June 2018|access-date= 22 June 2018 |work=[[Newshub]] |date= 21 June 2018 |quote=She is only the second world leader in history to give birth while in office. Pakistan's former Prime Minister Benazir Bhutto gave birth to a daughter in 1990.}}</ref> Ardern was also the first prime minister to lead a single-party [[majority government]] since the introduction of MMP, doing so from 2020 to 2023.<ref>{{cite news |title=Election 2020: Jacinda Ardern claims biggest Labour victory in 50 years |url=https://www.stuff.co.nz/national/politics/300135131/election-2020-jacinda-ardern-claims-biggest-labour-victory-in-50-years |access-date=22 June 2021 |work=[[Stuff (website)|Stuff]] |date=17 October 2020 |language=en}}</ref>