In an interview with The Telegraph, the American author referred to a friend of his who had 'drunkenly' looked for images of 16-year-old girls and was later jailed.
He said: "We have prisons now filled with guys my age. Sixty-year-old white men in prison who've never harmed anybody, would never touch a child."
"But they got online one night and started surfing around, probably had too much to drink or whatever, and pushed the wrong buttons, went too far and got into child porn."
He also said he thought that sentences for such offences were too harsh, adding: "We've gone nuts with this incarceration."
But Simon Bass, CEO of CCPAS, told Premier the writer, who has sold millions of copies of his legal thrillers worldwide, ought to "stick to fiction he knows about and not invent fiction around child abuse".
He added that the author's comments were "dismissive of children being harmed", saying it was "naivety at best and, at worst, a dismissal of understanding that when we talk about indecent images of children, we're talking about a crime scene where children have been abused."
Mr Bass went on to explain why the viewing of sexual images or videos of under-18s is, in itself, a form of child abuse: