If you’re specifically looking for affiliate software which you can plug into your New Zealand based site one option is the iDevAffiliate software package. While I do not have direct experience with this package, it is implemented as the Find It Online Affiliate Program which I have just signed up for and have to say it seems very user-friendly. Sign-up was simple, the information I wanted quickly (link code and payment levels) were available without fuss and the site appears to have plenty of good functionality. At $99 (USD) this affiliate software is well priced assuming it completes all that is says it does. I’ll be using the software on the Find It Online program and will report back on it’s features after more use.