Welcome back CK. Good to 'see' you on here again.
You could take a look at the
NZ Website List under Employment to find a few job agents but I'm sure there are many more kicking about. An alternative is to look through the
NZ Yellow Pages to find likely potential employers. If they have email addresses or phone numbers, you could contact them to see if they are looking for staff.
It would never hurt to have contacts in NZ to help with the job search, but I'm sure most folks wouldn't have such a luxury and still manage to find jobs on their own. Congratulations on receiving your ITA letter. A step in the right direction.
Here's a link to the
NZ Dept. of Conservation which might give you a lead to finding conservation work.