Shopify now has support for the New Zealand based payment gateway SecurePayTech, thanks to a member of the Shopify community. Jasper Bryant-Greene had originally requested the gateway in the Shopify forums, but he decided to take matters into his own hands and write the code for the gateway himself. He then contributed the code to ActiveMerchant. More information about contributing payment gateways to ActiveMerchant can be found in the ActiveMerchant Guide to Contributing.
Some more information about SecurePayTech from their homepage:
SecurePayTech.com provides secure and affordable credit card authorization and processing services for on-line businesses. Comprehensive reporting of individual transactions combined with historical trend analysis keeps you firmly in control of your business.