Welcome to the forums
Is this the returning resident's visa? I'm not sure whether the returning resident's visa is the same for partnership as it is for skilled migrants (the category I've applied under), but if so, you get your first returning resident's visa automatically with your visa:
Then, after two years, you can apply for an indefinite returning resident's visa, which gives you the ability to come and go as you please, if you fulfill certain criteria (the most often cited one being resident in NZ for at least 184 days (i.e. 6 months) each year of the two years)
Hope this helps!