There's world wide shortage of airbags ... If you can imagine how many E46s were produced and how almost every single one has to be recalled, it doesn't just happen over night. BMW NZ knows as much as what they are supplied with in terms of recall notices from Germany, who in turn must rely on Takata Japan to say which batches were affected.
They don't just miraculously get shipped 20,000 airbags overnight. My understanding is they get about 100 at a time if that. So it's a slow process and the most litigious countries with the highest possible legal ramifications get priority as you can expect.