The Welsh star coached Leanne Mitchell to victory on the singing contest last year (12), helping her beat three other finalists to land a recording contract.
But her debut album flopped, selling less than 1,000 copies, and Sir Tom came under fire after Mitchell recently revealed she hadn't heard from him since The Voice wrapped.
However, fellow coach O'Donoghue has hit out at the fledgling singer, suggesting that Mitchell herself is to blame for her poor album sales.
He tells Britain's The Sun, "That's not my fault, that's not the show's fault, that's not the Bbc's fault, that's just her fault. You can take an artist like that and question their work ethic.
"I was told by Tom Jones, and by the label as well, that Leanne just did not want to work as hard as you have to work to be a pop star. She wanted to come on a show and win a singing contest. That's good for her, because she won the show. But it's not good for the premise of the show."