I have been talking to a fellow in NZ discussing semi-only stuff recently in relation to my MOSFET switches. He had some interesting info. Only recently has New Zealand allowed importing guns converted to semi-auto by the retailer. Before, you could not buy say from Hong Kong even if the gun was converted to semi-only before it was shipped.
M249s and other fullauto only gearbox guns are rejected from importation completely. There is even trouble if you want to import selector plates because they know what these are and can be used to convert a mechbox to auto. The point is there is plenty of fine print and it's more complicated than NZ = semi-only. And besides, is it seriously reasonable to face charges just because your BB gun can fire more than 1 shot at a time?
Of course much of it is silly - what do you expect when you have people who don't know what they're talking about making the rules for things they don't understand?