I've been to Oz and NZ a couple of times and have found Travel Mood to be a good firm. But some of the bast deals I had were with Leestravel.com. Check them out.
I tried STA and trailfinders but they tend to be student biased. which is great if youre a student. Not so great if you're not one. good luck.
I went with Travelbag and they were great, I was able to negotiate things like insurance transfers etc and they were able to beat any other company i had found,....try them i don`t think you`ll regret it.
Bobcat