Roman Catholic lay organisations have called out two major American retailers for selling costumes for this year's Halloween that are supposedly offensive to priests and nuns.

According to a report from Life Site News, the Catholic group called American Society for the Defense of Tradition, Family and Property (TFP) recently issued a statement calling as "immoral" and "horrible" two Halloween costumes being sold on the websites of Amazon and Walmart.

The two costumes being questioned depict a sexually excited priest and a pregnant nun. American TFP Vice President John Horvat said these costumes are "obscene" and "sickening."

"Amazon and Walmart are selling Halloween costume sets that are directly targeted to offend Christians and mock religion," Horvat told Life Site News.

The American TFP has also launched an online petition to condemn Amazon and Walmart's marketing of these offensive costumes, and calling these major retailers to pull out these products from the market.

In the online petition, which has so far garnered about 17,000 signatures, the Catholic group noted how these two mega retailers have removed some products in their line — including those that offend Muslims, homosexuals and transgenders — because of public outcry.

The Catholic League for Religious and Civil Rights meanwhile called on Amazon and Walmart to treat the clergy with the same respect and consideration as it extends to other groups.

Catholic League president Bill Donohue expressed concern on how the two retailers seem to have "no problem" offending Church workers.

"There are no excuses for what Amazon is doing, but Walmart is worse," Donohue said. "It likes to tout itself as a "Christian-friendly" store, yet when it comes to Catholics, it drops its guard. It is not a good cultural sign when corporate elites are more sensitive to cross-dressers than they are to Catholics."

Website links to the two offensive costumes are reportedly not working at times as of posting time.