There are two options: real time internet banking (POLi) or pago.

More details on real time internet banking

Pago:

Now you don’t need a credit card to book online AND there is no need to wait for funds to clear. That’s right, you can have a same-day confirmed booking AND pay cash! Here’s how:

If you are 14 years or over and have a New Zealand bank account, open a Pago wallet online here and top it up straight away at a any branch of the ASB Bank.

• Register for your wallet at www.pago.co.nz
• Find an ASB Bank branch near you here.
• Ask the person at the ASB counter to deposit the cash into 12-3456-0900123-022 (the Pago holding account) and
• Put your Pago wallet name in the particulars field (this is how we know which wallet to put the money into).
• Now you can go to the nakedbus.com website to book and pay using pago immediately using the money you deposited.
  

Need help with this?  go to http://www.pago.co.nz/