they claim it's the 5th largest show of it's kind in the world.
In some respects the population base of NZ alone is irrelevant because buyers from all over the world come to this show and a large percentage of those foreign buyers are Aussies (so not having representation at the show is showing a middle finger to a pretty big continent).
Further, even it was just a NZ population issue for some, take a look at how much wood we have, how much heating gets done with it compared to more built-up/urbanised sprawls in other countries. Like Half just said, our exchange rate is darn good (as is the Aussie-US rate), has been for a while now. The time for these manufacturers to be here is now but after two years almost of being exasperated and bewildered that they can't see or be bothered with, the potential gains they could make by being at this show and having decent representation down-under, it's hard not to be frustrated by their apparent indifference.
These splitters have merit. They aren't a silver bullet, but unless they are tested in all woods down here in NZ/Aussie who knows where the limits are? It may just be they have tested and don't want to publicly state their splitters can't handle our wood and instead just refrain from shipping them here?
Regarding the CE safety standards, I think many in such highly litigious countries can't get their heads around how our system in NZ (I can't speak for Aussie as I am still not 100% sure on theirs yet-a few loose ends to chase up) works. Sure, for some items, especially the 'lecky motor options, international standards are worthwhile, but there is actually no impediment that I am aware of to selling the petrol splitters here. Neither is there any potential liability for the manufacturers should someone take their hand off.
They aren't seriously complex bits of kit (although with many things, I suspect the devil is in the assembly detail), can be imported as parts and assembled here on a "made from local and imported ingredients" basis and from where I'm typing I can get to anywhere in NZ or Aussie and a few other South Pacific countries for that matter, within an 8 hr plane ride, and testing the waters down-under would not cost an arm and a leg.