This event was hosted by "RDANZI", more formally known as the Roller Derby Association of New Zealand.
I'm not entirely sure whether to classify this as an association patch or an event patch as it doesn't immediately indicate which it is. I suppose I'll wait and see if they stock it long-term. This particular event has another patch, but it's also the event where RDANZI unveiled this patch. The feather-like object on the helmet is actually a branch of a silver fern, the national plant of New Zealand. It can also be found on the logo of the national derby team of New Zealand.