A Facebook manual detailing the social network's restrictions on breastfeeding images and other uploaded content has been leaked to Gawker and reported by the New Zealand Herald and MSN NZ.

The "abuse violation handbook" says a photo that exposes a woman's nipples is banned, but man's nipples in pictures are acceptable. It further specifies that pictures of the act of breastfeeding are banned if nipples are exposed.

The Herald noted Facebook has previously been slammed by breastfeeding mothers whose photos were found to be unacceptable by content editors.

Obvious sexual activity, even if "naked parts" are hidden, people "using the bathroom", and "sexual fetishes in any form" are all also banned.

In contrast, graphic images of dead animals, bloody human wounds and crushed limbs are fine.

"Deep flesh wounds" and "crushed heads, limbs" are allowed "as long as no insides are showing", the document said.

The handbook goes beyond detailing photo filtering guides. It also mentions rules on reviewing text content.

Facebook does not condone "racist slurs" but allows such comments if they are made in a "humorous or ironic way," MSN NZ reported.

Facebook also approves pictures of people using cannabis, but not those of "drunk or unconscious" people, according to the Herald.

The Herald said the document was leaked to the Gawker site by a source within Facebook, and MSN reported the source was "a seemingly disgruntled former employee of Facebook."

The leaked document provides a glimpse of how Facebook manages its content.

The manual is reportedly the bible for workers hired via oDesk to respond to users who click on a "Report" button. It runs to 13 pages, according to the Herald, but MSN reported the rules are contained within a 17-page document.