Just over 60 years ago, on January 1, 1949, the British Nationality and New Zealand Citizenship Act 1948 came into force, which meant that most people living here on that day became New Zealand citizens.
It may surprise some that before that date, they were solely British subjects according to the law, but with the formalisation of New Zealand citizenship, most of us became New Zealanders as of right, and children born here from January 1, 1949 automatically became New Zealand citizens.
The Act is largely forgotten these days, except by constitutionalists and officials, yet it was one of the last of the constitutional apron strings that held us tied to the United Kingdom to be cut.
Although New Zealand has substantially been in charge of itself since 1856, our Parliament was legally subordinate to Westminister until 1947 when we secured full control with the Statute of Westminister Adoption Act.
In the 60 years since 1949, New Zealand has transformed itself; politically we have reconfigured what we understand to be democracy by using democratic means; economically we have become far more diversified than reliance wholly on agriculture; socially we are a truly multi-cultural nation.
We now have our own superior court, replacing the Privy Council, and it will likely become chiefly concerned with constitutional matters, especially those in which there is some connection or claimed connection to the Treaty of Waitangi, as the nation matures.
Virtually all new legislation now requires account to be taken of the principles of the treaty, which have not, be it noted, yet been defined in any constitutional document passed by our Parliament - by the people, in other words.
We have no substantive written constitution and hardly a mood to devise one.
When challenged to do so, we have hastily retreated.
Formal recognition of the treaty was rejected when proposed in 1980s and there has been no popular agitation for it since.
Yet we have adopted proportional representation and thus diminished the influence of the executive over the legislative agenda, and given minorities a voice.
More particularly telling for the future, so far as the origins of our citizenship base are concerned, is the change in the variety of countries from which new New Zealanders have come.
The top nine migrant origins recorded in the 2006 census were England (202,401), China (78,117), Australia (62,742), Samoa (50,649), India (43,344), South Africa (41,676), Fiji (37,746), Scotland (29,016), and South Korea (28,806).
According to the 2001 census, they were: England (178,000), Australia (56,000); Samoa (47,000), China (39,000), Scotland (29,000), South Africa (26,000), Fiji (26,000), Netherlands (22,000), and India (21,000).
Before 1950, New Zealand's migrant population was largely British Isles in origin, and it increased dramatically after the war especially when skills and people were needed, with the assisted scheme for immigrants from Britain, which was introduced in July 1947.
The scheme was extended to the Netherlands and some other European countries in 1950.
Large numbers of people also began arriving on their own initiative.
By 1971, the number of English-born in New Zealand had risen by over 66,000 from 1945, but the number of Irish had actually fallen and the Scots had risen by fewer than 4000.
New Zealand also sought other western Europeans who might be easily assimilated including between 200 and 350 each from Austria, Germany, Denmark, Switzerland, and Greece.
Some Europeans arrived as refugees.
By 1971, the proportion of our foreign-born population from countries outside the white British Commonwealth had doubled in 20 years to 30%.
The entry of the United Kingdom into the European Community and subsequent limitations on trade links established from colonial times encouraged governments in the 1970s to look to the Pacific, Australia and Asia as sources for new citizens, their labour and their skills.
In 1974, a review introduced a new non-racist immigration policy - the ending of the "white" preference - meaning that all prospective migrants beyond Australasia, British and non-British, could obtain entry permits, and the right of residence became based on skills and qualifications, not ethnicity or national origin.
The following year, the policy of assisted immigration from Britain ended.
The 40 or so years since have seen our communities transformed by population changes in physical appearance, in culture, and in individual contribution.
It may be fairly claimed that the vast majority of migrants who have become permanent citizens are ardent New Zealanders.
They may also value citizenship in its broader meaning rather more than born-and bred New Zealanders, who perhaps accept their rights unthinkingly not having had to fight for them.
Citizenship should never be taken for granted, for the very term conveys the rights - and the responsibilities - that form the basis of our democracy.
It is notable that the new Parliament, which will mark the passage of the British Nationality and New Zealand Citizenship Act 1948 in various ways later this year, also has a composition which reflects the diversity of New Zealand ethnicity today and of the various immigration schemes over the past 60 years: there are six MPs of Asian descent - our first Sikh MP and our first Korean-born member, a Pakistani-born and an Indo-Fijian member; there are four Pacific Islanders, at least 18 members identified as Maori - and National's Pansy Wong became our very first Asian electorate MP.
This Parliament is certainly the most ethnically diverse in our history, something of which all New Zealand citizens can be proud.
