“Some of their judges aren’t even singers and wouldn’t be able to sing a note, so what do they know?” he told The People.
“Every time I see one of these shows I think half the decisions are wrong and it really frustrates me.
Jones is one of the judges on new BBC singing show The Voice and says his frustration at watching the X Factor played a major part in him accepting the position.
He said a singing show should be all about a person’s talent and not a popularity contest relying on PR spin.
“Some of the judges don’t have the experience to be on talent shows – if you’ve only been in the industry two minutes, how can you offer advice?
“I have the experience and I listen to all sorts of music, so the advice I give will be valuable.”
A source from Simon Cowell’s camp dismissed Jones’s comments and accused the singer of being part of his own PR stunt.
“It’s a bit rich for someone appearing as a judge on a BBC show that hasn’t even started yet to criticise Simon,” the source said.
“Simon’s always held Tom Jones in high regard but he’s being drawn into a PR stunt by the BBC when he should know better.”