The judge told Heat that he was happy Simon Cowell's Britain's Got Talent had been pipping The Voice in the ratings.
"I hate The Voice," Walsh said. "I think everyone thought The Voice UK would be like the US version, and it's not.
"It's dull and boring. I'm glad BGT is winning the ratings battle - it's much better."
Asked if he would ever be a coach on The Voice, he replied: "No way, it's not great TV. It's like Fame Academy all those years ago.
"The best thing about it are the revolving chairs, and once you've seen that, the novelty wears off."
Walsh dismissed The Voice's will.i.am as "ridiculous", adding: "What's that man's real name anyway? It's not will.i.am, is it?
"He thinks he's got all the answers, but if he didn't have Fergie in the band, where would he be?
"Fergie is the real star. I would love her on The X Factor, and to be a judge on the show."
He added: "The X Factor is the biggest show on TV and the other shows are just copying us with their silly chairs.
"Simon Cowell is the king of TV and if he's not involved then it's not good."