Not really. If you don't care about due process the way we try to (or pay lip service to) in the USA, you can just issue orders like this. It's not actually a law; it's just an order changing the definition of terms in the law that was passed back in 1983.
That's a U.S. perspective and not the way the law is written in NZ. From what I've read, there's some wiggle room for removing attached accessories but trying to turn in an AR without the upper, bolt, barrel, etc. isn't, as far as I can tell, going to work.
While we know they won't enforce it that way right now, we don't know what will happen in the future. I imagine that if NZ gun owners are still shooting .22LR in a couple of generations, some anti-gun geek will realize the truth of what you've posted. Then the literal wording of the order can be used to confiscate lots more rifles.
