An actress best known for playing a young Superman’s friend has pleaded not guilty to charges she helped recruit women into a cult-like organisation.

Allison Mack was charged with sex trafficking after US prosecutors said she worked as a slave “master” recruiting women to a group led by a man who sold himself as a self-improvement guru to the stars.

Mack entered her plea in federal court in Brooklyn. The judge refused a request by her lawyers to release her without bail.

Mack starred in Smallville, a show about the early life of Superman that ended in 2011.

Prosecutors say she helped recruit sex slaves for leader Keith Raniere and his group called NXIVM.