Even though this has been a requirement for NZ passport holders since March 2016, we find that a lot of travellers are still unaware that Canada introduced entry requirement, known as an Electronic Travel Authorization (eTA), which they need before they board a flight to Canada. Entry requirements for other methods of travel (land, sea) will not change.
eTA is a new entry requirement for visa-exempt foreign nationals travelling to Canada by air. It will allow Canada to screen travellers before they arrive. The authorization is electronically linked to your passport and is valid for five years or until your passport expires, whichever comes first. Applying for an eTA is an easy online process that will take just a few minutes. It only costs $7 Canadian. All you need is your passport, a credit card, and an email address.
The website for applications can be found here