The Australian radio and television personality, who used to be married to singer Tamara Jaber, revealed that his feud with TV presenter McManus was ignited when McManus mocked Jaber's music career.
Sandilands said: "I'll tell you what happened... we used to go on Rove's show and like everyone else I thought he was nice. And when Tamara brought those songs out a few years ago and the newspapers started caning her and lying, saying I was the only person playing it... Rove jumped on the bandwagon and started to have a go.
"So when he started sinking the boot in, I started hating him and then when Rove's wife [Belinda Emmett] passed away, he and I met up again and he said, 'I'm sorry, I understand, I shouldn't have gone there with the Tamara situation'.
"Then two weeks later he was an asshole to me and Tamara on his TV show... Everyone thinks he's cookies and cream when he's a little pr*ck... he's a little asshole. I let bygones be bygones because his wife passed away and I thought, 'You came in here, you used us, you pretended that you were sorry'."
When asked about McManus's new show, Sandilands responded: "Good luck on Fox8 you piece of s**t cable host."
McManus said of the feud: "I have no idea why. As I keep saying to people, for there to be a rivalry it has to go two ways and it's just from him. I have no feelings for him either way."
Sandilands has recently caused controversy with various outbursts against other celebrities. He labelled radio star Merrick Watts a "fat slob" and then launched a tirade against supermodel Megan Gale. He has also now been reprimanded by TV bosses after blabbing about a potential new series.