Steve Baron: MMP - To Disembowel or Develop?
So what does history tell us about our voting system and why did we change to MMP? For a start, in 1978 and 1981, the Labour Party received more votes than the National Party but National remained the government, because they held more electorate seats. That is how First Past the Post (FPP) works. In 1978 the Social Credit Party (now Democrats for Social Credit) received sixteen percent of the vote, but only one seat in Parliament, then twenty one percent of the vote in 1981 which gave them only two seats in Parliament. In 1984 the New Zealand Party received twelve percent of the vote, but no Members of Parliament. These results, along with a growing distrust of politicians due to many broken election promises, and New Zealander's innate belief in fairness, led to calls for a Royal Commission, and change.
https://betterdemocracynz.blogspot.com/2010/02/mmp-to-disembowel-or-develop.html