You can set up a direct debit from a New Zealand bank account via Stripe Billing.
To set this up, add a payment method under your billing profile at https://secure.privatebox.co.nz/billing.
If you are not on Stripe billing yet, you can use the “migrate to stripe billing” to change the account over. If this can be done automatically, then allow 15 mins for the move across. If it has to be done manually, allow a day or two.