Their search function tells us that 12 comic books were deemed objectionable from 2000 to 2015, all in 2001. Why 2001? I'd guess that some shipment of comic books got held at customs and OFLC was asked to classify it.
Here is the justification banning one of those comic books: it's classed as objectionable. I can't link it because their database back end doesn't support that, but here's the decision for Spunky Knights.
You can go to jail for up to 14 years for importing it, 10 years for possessing it.
Here's the justification for potentially throwing somebody in jail for owning a comic book.
SUMMARY OF THE REASONS FOR DECISION:
The comic entitled Spunky Knight has been classified as objectionable.
The comic contains cartoon images rendered in a style known as Manga Lolikon, and involves female characters with child like features. The comic contains seven separate stories each of which is used to provide a context within which explicit sexual activity is depicted.
In some stories, female characters engage in sexual activity with mythical creatures. The publication is not considered to promote or support, or tend to promote or support, bestiality in terms of s3(2) of the Films, Videos and Publications Classification Act (FVPC Act) due to the fantastical nature of the stories.
The publication has been considered under s3(3) of the FVPC Act. The publication depicts sexual violence and coercion in association with sexual conduct, and degrades females to such a high extent and degree, that the availability of the publication is likely to be injurious to the public good. The publication is therefore classified as objectionable.
The New Zealand Bill of Rights Act 1990 has been considered in relation to this publication. The classification represents the minimum interference with the freedom of expression consistent with preventing likely injury to the public good.
OFLC Ref: 100232Spunky Knight. Make sure it's not in your collection. It's available at Amazon.com (out of print) for $57. It'll cost you a lot more than that if New Zealand's police find out you've got a copy.
The decision summary only cites s3(3) as reason for banning. That by itself wouldn't be enough to put the publication into the special-extra-banned child porn designation, but the Censor's Office, which continues to have NZ's single best twitter feed for helpful government answers, confirms that the full decision document - available on request - refers to sections including 3(3)(a)(iv), which means you're into repeat offender territory where presumption of imprisonment applies.
New Zealand criminalises possession of comic books available on Amazon.com. If you've a prior record, there's a presumption of imprisonment for owning a comic book. Asylum stuff.