(2) Whether any particular published matter is or is not a blasphemous libel is a question of fact.

(3) It is not an offence against this section to express in good faith and in decent language, or to attempt to establish by arguments used in good faith and conveyed in decent language, any opinion whatever on any religious subject.

(4) No one shall be prosecuted for an offence against this section without the leave of the Attorney-General, who before giving leave may make such inquiries as he or she thinks fit.

The BBC has this backgrounder on the offence, which we inherited from the UK along with the rest of our colonial baggage ... at which point we we might note that England and Wales (but not Scotland and Northern Ireland) got rid of it in 2008.

Q: What is the blasphemy law?

The legal notion goes back centuries - as faith was seen as being the heart of society, to challenge or offend it was thought to threaten the fabric of society.

The present law of blasphemy is based on decisions made by nineteenth century courts. In an 1838 case it was restricted to protect the "tenets and beliefs of the Church of England". 

Q: What actually constitutes blasphemous libel?

This is a more obscure. Some academics say the crime has been expressed so many ways it is hard to say exactly what behaviour would be considered blasphemous.

During a private prosecution in 1977, the trial judge said blasphemous libel was committed if a publication about God, Christ, the Christian religion or the Bible used words which were scurrilous, abusive or offensive, which vilified Christianity and might lead to a breach of the peace.

How important a bit of our law is it? Well, New Zealand's last prosecution for blasphemous libel occured nearly a century ago in The King v. Glover [1922] GLR 185; when the editor of the Maoriland Worker, John Glover, was prosecuted for publishing Siegfried Sassoon's anti-war poem, Stand-to: Good Friday Morning:

I’d been on duty from two till four.
I went and stared at the dug-out door. 
Down in the frowst I heard them snore.
‘Stand to!’ Somebody grunted and swore.
Dawn was misty; the skies were still; 
Larks were singing, discordant, shrill;
They seemed happy; but I felt ill.
Deep in water I splashed my way 
Up the trench to our bogged front line.
Rain had fallen the whole damned night.
O Jesus, send me a wound to-day,
And I’ll believe in Your bread and wine,
And get my bloody old sins washed white!

Demonstrating good sense and tolerance, after a short deliberation 12 ordinary New Zealanders acquitted Glover of the charge, albeit supplementing their verdict with the comment that "similar publications of such literature ought to be discouraged".

And that has pretty much been the end of the law's application in this county. For despite the occasional effort by conservative Christian figures to have blasphemous libel charges brought against, inter alia, those who display religiously offensive artworks (Serrano's "Piss Christ") or broadcast sacrilegious television shows (South Park's "Bloody Mary"), the requisite permission under s.123(4) has been refused. And I'm willing to bet pretty much anything you'd care to name that such permission will never be given in the future - meaning that the provision is for all intents and purposes a dead letter.

Instead, protection of religious sensibilities now falls under the country's general criminal and censorship laws - as with the banning of Cradle of Fith's "Jesus is a c**t" T-Shirt in 2008, which in was deemed objectionable (and thus illegal to possess) as it "it fuses religion with the most aggressive, misogynistic word in the English language, with sexual activity depicted on the front that implies even celibate women can not resist sex." 

Note, however, that such censorship decisions cannot be made on the basis of religious offence alone. You instead need to link it to some depiction of "sex, horror, crime, cruelty, or violence in such a manner that the availability of the publication is likely to be injurious to the public good." So an attempt to, for instance, have the NIN song "Heresy" deemed objectionable for declaring that "Your god is dead and no-one cares" would be doomed to failure, irrespective of how upset it may make a religious believer.

Of course, there are some situations where playing that song could lead to criminal charges. If, for example, I were to hire a sound truck and blast it at volume outside a mosque or church whilst believers were holding a service, I might very well be arrested, charged and convicted for behaving in a disorderly or offensive manner. But the same thing could very well happen to a group of christians or other believers loudly protesting against a play that they believe to be blasphemous in a way that is designed to disrupt it. Such offence provisions are facially neutral as to the cause of the offence/disorder at issue, not religion specific. Which is how things should be in a modern, secular democracy.

So if politicians' deeds match their words and s.123 of the Crimes Act is consigned to the history books, then that's great. The only real issue for me is that it took so long to get around to doing it.