A baby's T-shirt bearing the slogan "they shake me" has sparked an angry online response from parents.

A complaint about the T-shirt was posted on the popular parenting blog Mamamia this morning, sparking an email and Twitter campaign against the company responsible, Cotton On Kids.

"They shake me" t-shirts for babies are commonly found at online stores.

"What the hell are you people thinking and how dare you try to turn children into the sickest kind of human billboards to advertise your smart arse and grossly insensitive slogans?" read the blog post on Mamamia.

"What's next Cotton On? Kids t-shirts that say 'My Parents Sexually Abuse Me'?"