Back in 1990, then Minister of Justice Geoffrey Palmer had a paper published in the VUW Law Review on "The reform of the Crimes Act 1961". This covered the history of New Zealand's criminal law and gave a brief overview of the changes proposed in the 1989 Crimes Bill. This is what it had to say on sedition:
[T]he existing provisions relating to sedition have not been repeated. Sedition offences originally derived from the Common Law and were either seen as attacks upon the Established Church or some other dispute or matter likely to disturb the public order to a serious degree.
In the latter half of the nineteenth century, major sedition trials in New Zealand involved Maori leaders, such as Rua. By 1900 sedition worldwide centred on such matters as industrial, political and racial disputes, and a few religious disputes. The last two reported cases in New Zealand occured in 1914 and were concerned with inflammatory statements made by the accused during a waterfront strike. Ambrose v Hickey in 1922 involved the question whether a pamphlet was seditious, but was prosecuted under regulations made under the War Regulations Continuance Act 1920.
[This history seems to be based solely on what could be extracted from New Zealand Law Reports, and ignores several celebrated cases, such as that of Bishop Liston]
Justice Department statistics reveal that two cases involving sedition were tried summarily in 1967 and resulted in convictions. No other records of these minor cases have been found. The main point to note, then, is that the offences are rarely used. Where what might be thought of as seditious utterances arise today, and unrest results, they would be more properly dealt with by existing offences relating to public order.
Sedition should not be a crime in a democratic society committed to free speech. Libelling the government must be permitted in a free society. Indeed, on my recent visit to the Soviet Union I was told that changes are proposed there which will severely cut back existing offences of this nature. Only specific acts aimed at overthrowing the Russian Government will be offences; dissenting opinion will not.
(Emphasis and link added).
Unfortunately the bill did not pass, and so we are still left with an archaic regime which compromises freedom of speech - and one possibly worse than the Russians (formally) have. Isn't that a lovely thought?