Walsh has previously claimed that Forsyth "shouldn't even be alive" and that he should "bow out gracefully" and "go home to sit on his sofa and drink Horlicks".
In a new interview with the Radio Times, Walsh made another dig at the 84-year-old, commenting; "My ambition's to get to 10 years [on The X Factor]. After that we'll see.
"I don't want to be like Brucie. I'll know when it's time to give it up."
Walsh also took a swipe at Sir Tom Jones and The Voice UK, claiming that the Welsh singer looked "lost".
Forsyth usually mocks Walsh and The X Factor during his warm-up act for Strictly, branding the Irish music mogul a "jumped-up karaoke judge" and the ITV talent show a "fireworks display".
The X Factor returns on Saturday, August 18 at 8pm on ITV1.
[X Factor Judges & Hosts - Photo Gallery]
Copyright: ITV Thames/Syco