The billboard, which featured a photo of the punk icon's beaten face, suggested Iggy had been tortured to endorse the Baby singer as "the future of rock 'n' roll".
However, it appears the human rights officials didn't ask for the Lust For Life singer's full permission before releasing the powerful new ad, and now they've apologised.
A new statement reads: "Even though we acted in good faith, we would like to apologise to Iggy Pop for having done so.
"The overall goal of this campaign is to try to influence people's ideas on the use of torture. According to surveys, a shocking number of people believe that 'torture may sometimes be useful' - more than 36 per cent of people even think that torture is justified in some cases. This is unacceptable, and we illustrate this reality with the message that a man who is tortured will say anything in order to escape this awfulness, using provocative images and statements to attract public attention.
"We would therefore also like to make it clear that the statement attributed to Iggy Pop that he believes Justin Bieber is the future of rock and roll does not represent Iggy Pop's personal opinion, but was part of the creative process for this campaign and was intended to be ironic."