Images and videos of a teenage boy forcibly hooded and tied to a chair in a Northern Territory detention centre were taken off Facebook because they showed a boy's bare bottom.
The disturbing images - which sparked an immediate royal commission - were aired on the Four Corners program on Monday night and shared widely on its Facebook page and individuals' pages.
But on Tuesday morning the images and videos disappeared without explanation.
"These videos were reported to us by members of the Australian public and our community operations team promptly reviewed and removed them for containing child nudity," a Facebook spokesman said.
"Upon further review, we have restored one of the videos because it does not contain such imagery.
"We review millions of reports each week and from time to time we make a mistake and work to rectify this as soon as we become aware of this.
"The second video does contain child nudity and so we cannot restore it."
Facebook said its Community Standards do not allow any child nudity to be shared, even if it's shared for the purpose of condemning it.
ABC Director of News Gaven Morris said Facebook removed one of the posts "in error" and it has been restored.
"Facebook has told us the other video contravenes its policy on child nudity, as it shows a boy's bare bottom," Mr Morris told AAP.
"ABC News gave careful consideration to publishing these images, which are evidence of the mistreatment of a child and not in any way gratuitous, and we believe their publication is strongly in the public interest.
"We have expressed our concerns to Facebook about their handling of this matter."
Four Corners executive producer Sally Neighbour said on Twitter she was "flabbergasted" that the images were removed.
