New Zealand is a constitutional monarchy. And it is founded on both sexual and religious bigotry. The succession of the English monarchy is governed by the Act of Settlement 1701 (UK), which enshrines not only male primogeniture, but also anti-Catholicism. It bans Roman Catholics, or anyone married to a Roman Catholic, from ascending to the throne. And it requires the English monarch to "join in communion with the Church of England" - a gross violation of the freedom of religion.
Now the UK government plans to repeal it. It's about bloody time. Monarchy is bad enough, bigoted monarchy is worse.
Tthe repeal will require the consent of other Commonwealth countries. In New Zealand it will also require a law change, as the Act is still part of New Zealand law. Which means that it puts the monarchy, and by implication, a republic, on the political agenda, whether the government likes it or not. If we're going to muck about with 300-year old legislation, we might as well do away with it - and the monarchy - altogether, and leave it to the British.
[Hat tip: Larvatus Prodeo]