The answer lies in the emerald city, just follow the yellow brick road, befriend a few strange creatures along the way, defeat the wicked witch of the west and always, and I truly mean always -Skip-
Well, you see, the Kraken wanted to build a clubhouse so he got some boulders but he couldn't be bothered to finish it so he just let the boulders move away into the sea and they ended up at New Zealand.
The last time I checked a leprechaun kicked me up the butt and said it's where all the chocolate money comes from; the gold is the golden paper that covers the chocolate.
They ate too much green chocolate when they were younger. Green chocolate is very bad for growth, this is also , incidently, why they give gold chocolate to people who find it (they are bitter about eating the green chocolate)