The New Zealand Labour Party formed as a political party in 1916, bringing together socialist groups advocating proportional representation and "the Recall" of Members of Parliament, as well as the nationalisation of production and of exchange. Its origins lie in the British working-class movement, heavily influenced by Australian radicalism and events such as the Waihi miners' strike.
The leadership, generally UK-born colonial immigrants to New Zealand, sufferred widespread imprisonment for opposition to conscription in World War I, but the Party survived to grow during the 1920s. The rigours of the Great Depression brought Labour (fronted by Michael Joseph Savage) to power in a landslide election in 1935.
Vigorous programmes of social and welfare reform, aided by political pacts with the Maori Ratana movement, kept the Labourites in Government in the 1938 election, despite internal disputes and the ultimate expulsion of John A. Lee.
Peter Fraser succeeded Savage as Prime Minister after the latter's death in office in 1940.
Labour lost office in the 1949 elections, failed to capitalise on the Waterfront Strike of 1951, and remained in the political wilderness of opposition until (barely) winning the election of 1957 under the leadership of Walter Nash, the last foreign-born head. Arnold Nordmeyer's [in]famous Black Budget dashed any hopes of a second term at the election of 1961, and the Party had to await the advent of Norman Kirk (Big Norm) before regaining the Treasury benches in the 1972 elections. Kirk's death in office left the Party (subsequently led by Bill Rowling) unable to win against the Muldoon landslide in the election of 1975.
After a long period in opposition, with politics dominated by an increasingly authoritarian Muldoon, David Lange restored Labour's fortunes in the 1984 elections. The resulting period was tumultuous, with Labour's controversial ministers Roger Douglas and Richard Prebble driving rogernomics, a rapid introduction of "free market" reforms and privatisation of government assets. However a widely popular anti-nuclear-ships policy gave something to the left wing of the party. Constant economic upheavals eventually saw the retirement of Lange from the Prime Ministership and his replacement first by Geoffrey Palmer in 1989, then by Mike Moore in 1990. However the changes could not save the party and it lost the election in 1990 to National's Jim Bolger.
During the period in opposition, Helen Clark as Labour leader achieved a measured repudiation of rogernomics and (eventually) engineered a return to office in the election of 1999, and subsequently reelection in the election of 2002
The New Zealand Labour Party of 2003 has less socialist militancy, sparser Trade Union support and a broad agenda of centre-left co-operation with the Progressive Coalition while toying with notions of the Third Way and of Social Democracy. It remains by far New Zealand's largest electoral bloc, but under MMP electoral law seems less likely to govern alone than in coalition.
The following is a complete list of former Labour Party leaders.