Upvote:1
It is completely flexible.
What matters is that once you are granted your visa you get 1 year to enter the country (unless different from Australia).
Upvote:3
There is no obligation for you to arrive on your date of intent to travel. From United Kingdom Working Holiday Visa (click on "All visa conditions"):
You must come to New Zealand within 12 months of the date your visa is granted.
After you arrive in New Zealand, you can come and go from New Zealand as many times as you like before your visa expires.