The document, examined under the Films, Videos & Publications Classification Act 1993 (FVPCA), is deemed objectionable for a number of reasons.
"It promotes, encourages and justifies acts of murder and terrorist violence against identified groups of people," Shanks said.
"It identifies specific places for potential attack in New Zealand, and refers to the means by which other types of attack may be carried out. It contains justifications for acts of tremendous cruelty, such as the deliberate killing of children.
"We have dealt with terrorist promotional material before which was deliberately designed to inspire, encourage and instruct other like-minded individuals to carry out further attacks. For example we have found a number of ISIS publications to be objectionable in previous decisions. This publication falls in the same category."
An objectionable classification for this publication is considered to be a justifiable limit on freedom of expression under the Bill of Rights Act in this case, the statement from the office said.
"There is an important distinction to be made between 'hate speech', which may be rejected by many right-thinking people but which is legal to express, and this type of publication, which is deliberately constructed to inspire further murder and terrorism," Shanks said.
"It crosses the line."
The office said it realised the publication had been widely reported on over the past week, with many media outlets publishing commentary on it, and sometimes providing links to it or downloadable copies.
The statement added many New Zealanders may have read it, possibly seeking answers for why this "dreadful atrocity took place".
Most people reading the publication will not be harmed by it, the statement said.
"Most New Zealanders who have read this will simply find it repellent. But most New Zealanders are not the target audience. It is aimed at a small group who may be receptive to its hateful, racist and violent ideology, and who may be inspired to follow the example set by its apparent author."
It is an offence to possess or distribute an objectionable publication. The office said people who have downloaded this document, or printed it, should destroy any copies; including the media.
"That use of excerpts in media reports may not in itself amount to a breach of the FVPCA, but ethical considerations will certainly apply," Shanks said.
"Real care needs to be taken around reporting on this publication, given that widespread media reporting on this material was clearly what the author was banking on, in order to spread their message.
"We also appreciate that there will be a range of people, including reporters, researchers and academics, who will be in possession of the publication for a range of legitimate purposes, including education, analysis and in-depth reporting. Those individuals can apply for exemptions, so they can legitimately access and hold a copy."
Information on this process can be found here: https://www.classificationoffice.govt.nz/news/latest-news/christchurch-attacks-press-releases/
To report harmful content on Twitter: https://help.twitter.com/en/rules-and-policies/twitter-report-violation.
To report harmful content on Facebook: https://www.facebook.com/help/181495968648557
To report harmful content on Instagram: https://help.instagram.com/519598734752872
To report harmful content on YouTube: https://support.google.com/youtube/answer/2802027?hl=en
Any harmful content should also be reported to the Department of Internal Affairs: https://www.dia.govt.nz/web/submitforms.nsf/cencomp</strong>
