I’m not aware of any travel cards in New Zealand that allow you to load foreign currency directly. All the major cards only allow you to load NZD and then “buy” the foreign currency at their rate.
ANZ used to have a great card of their own (I believe it used the ANZ Australia back end) but they ditched this a few years ago in favour of reselling a white label Travelex offering. A number of other banks also just resell the Travelex offering, and Air New Zealand are now using this as well for their OneSmart card.
I personally just use my credit card overseas for the vast majority of purchases and take some cash with me. Since I don’t tend to use a lot of cash I find this system works well for me.