It's down against USD but up against Australia? It's also only fallen to what it was a few months ago.
Seeing as it's up against AUD I'm more inclined to think that the fall is more to do with US rather than NZ. Also, NZD is in the top ten most traded currencies in the world, the government is only a part of what it's worth.
I remember a few years ago the reserve bank tried to use some of it's foreign currency reserves to halt the growth of NZD but that made barely a blip.
But, we're an exporting country - ultimately it's good for our economy for the dollar to sit a little lower than our partners.