Conservative advocacy group the American Family Association (AFA) has extended its protest of the controversial reality show "Sex Box" to its advertisers.

The group asked supporters to contact the WEtv channel, its owner, AMC Networks, and the show's only national sponsor, Arm & Hammer, to get the programme off the air.

"Sex Box" was adopted from a popular British series of the same name, and is produced by Relativity Media. On the show, couples undergo counselling after they have sex inside a closed box on set.

There are no cameras or microphones inside the box, but a panel of relationship experts sits outside the container while the couple are inside. The idea is that the couples will be more receptive to the experts' advice after they emerge.

The AFA division OneMillionMoms.com (1MM) called the premise "disgusting."

"Although the audience doesn't see the couples having sex, the titillating premise that we're watching while real couples are engaging in an intimate act inside the box on stage is obviously the hook WE tv is using to lure viewers," executive director Monica Cole said.

The group pointed to the lack of national sponsors as evidence that "Sex Box" is "culturally degrading programming," and called for concerned parents and grandparents to email, call, Facebook, and otherwise air their grievances to Arm & Hammer.

The Parents Television Council also began a petition to get "Sex Box" off the air.

"We have had success in stopping other shows before like Oxygen's 'All My Babies Mamas,'" president Tim Winter told FOX411 last month.

"Cable networks really feel it when advertisers start to leave. What we want is this network to be tossed off by the cable network."