Fiji, I think I have atleast narrowed it down to the genus. There is a pic, but no species name.
It's possibly a Echniothrix for sure, and possibly calamaris.
Scroll down in the link to the section titled similar species. It has a Echniothrix pictured(exactly like yours), and also describes a Diadema species. It tells that both have banded spines, but only Echnothrix have tubular spines. It would also seem, they are somewhat poisonous. It says they can inflict painful stings, but nothing more.
http://www.edge-of-reef.com/inggris/laben.htm