An atheist organisation launched an anti-church campaign with a Christmas theme on Monday, targeting the southern states.

The American Atheists placed billboards in Memphis, Nashville, St Louis, and Ft Smith, Arkansas, and co-sponsored an atheist billboard in Milwaukee with the Southeast Wisconsin Freethinkers.

The ads feature a young girl writing a letter to Santa Claus that reads: "Dear Santa, All I want for Christmas is to skip church! I'm too old for fairy tales."

American Atheists President David Silverman said the billboards are meant to target "in-the-closet atheists" who may not want to attend church but feel obligated to do so.

"Even children know churches spew absurdity, which is why they don't want to attend services," Silverman said in a statement. "Enjoy the time with your family and friends instead.

"Today's adults have no obligation to pretend to believe the lies their parents believed. It's OK to admit that your parents were wrong about God, and it's definitely OK to tell your children the truth."

While previous American Atheists billboards have targeted high-traffic areas such as Times Square, the newest billboards will be placed in less populated areas near schools and churches. Attempts to erect the anti-Christian billboards in Jackson, Mississippi were denied by lessors, a predicament the atheist organisation found disturbing.

"The fact that billboard companies would turn away business because they are so concerned about the reaction by the community to a simple message that not everyone goes to church and not everyone believes in gods shows just how much education and activism on behalf of atheists is needed in the South," Public Relations Director Danielle Muscato said.

The billboards also promote the American Atheist National Convention, which will take place during Easter weekend 2015 in Memphis. The ads will be on display until December 24.