I have both of these movies. Undead is amazing, made by the same brothers who created Day Breakers. I haven't seen many Australian zombie films, Undead could be the only one I know of. Back in the 60s the 70s and the 80s there was quite a bit of competition between the Italian and American film makers when it came to horror and zombie movies.
I've spent a lot of time watching these movies, I have Japanese, Chinese, Scottish, English, Australian, Sweedish, Mexican and yadda yadda yadda. To be honest, I think us in the good ol' USofA make the best zombie movies. We just have so many it's hard to compete.