Foreign Passport holder with NZ Permanent Resident

Hi there,
I have Afghanistan passport with New Zealand permanent resident and I want to go China to visit my girlfriend and her family for one or two months.

I read a paragraph above that ( non New Zealand citizens ) must go to Wellington to apply for visa, but I am living in Otago and study there. Could you please tell me ( what documents should I prepare and what type of visa can I get).

Also do I still need to go Wellington for my visa?
Thank you for your time.