Images of stars such as Paris Hilton and Khloe Kardashian cuddling baby orangutans in Dubai lower the public's perception of the animal and encourage trafficking, said the U.N.'s Great Apes Survival Partnership (GRASP).
"Every time a famous face is seen cuddling an ape in this way, it undoes years of our work," GRASP coordinator Douglas Cress told CNN. "It lowers the value of the animal, and the public sense of conservation drops."
"If you can laugh at an animal, or you can empathize by how human it is in clothing, then you rob it of its natural wildness. It becomes something comic, or a pet," added Cress.
"So when you have a celebrity like Paris Hilton holding an orangutan with a dress on, they can impact millions of people because their audience is so huge."
The orangutan pictured -- called Dior -- also appears to feature in an Instagram image with reality TV star Khloe Kardashian.
Kardashian has 47.8 million followers on Instagram; Hilton has 5.7 million.
Real Madrid footballer James Rodriguez also posted a photo of himself cuddling an orangutan while on holiday in Dubai.
The celebrities' agents did not immediately respond to CNN's request for comments.
Many primates arrive at private Middle East zoos through illegal means, said Cress, whose organization now plans to carry out an investigation into trafficking in the region.
"The Middle East is both a transit region, and where many rich families have private menageries," he said.
"These animals are easily trafficked because law enforcement is relatively weak against a wealthy elite that appear untouchable."
In the United Arab Emirates, residents are able to keep wild animals as pets, provided they have a permit.
Cress said that when baby monkeys or other primates are taken from Asia and Africa, their families are often killed in the process.
"In the case of chimps, which live in families of 10, they're not going to just give their babies up. So you have to kill a lot, to get one," he added.
"They are then sold to a middleman, then to an exporter, and transported in suitcases and shopping bags -- it's that blatant."
Each week there are roughly two ape seizures by police around the world said Cress, adding "that's just the tip of the iceberg."
The organization plans to launch an online database of global seizures later this year.