G’day Marcel,
To be honest, I don’t know if it can. This plugin uses the Direct API, which posts payments through the Australian eWAY gateway. It also currently forces the currency to AUD for forms that use it.
I suggest you ask eWAY whether their Direct API can be used for NZ payments, and let me know their response. If it can, then I’ll open up the currency restrictions to include NZD.
I’ll have a new eWAY plugin available by end of December with support for multiple currencies, among other things. It won’t be free though.
If all you need is a free payment integration for Gravity Forms, take a look at Gravity Forms DPS PxPay. That plugin uses Payment Express’ hosted payment form, and supports NZD.
cheers,
Ross