Speaking to Now, the former Boyzone manager insisted that the new pair are closer than former panellists Cheryl Cole and Dannii Minogue.
"There was always rivalry between Cheryl and Dannii. It wasn't a bad thing, but I think Kelly and Tulisa get on better," the 59-year-old said.
However, Walsh suggested that Destiny's Child singer Rowland's lack of knowledge on English music may cause friction between the pair.
"They're going to fall out, though, especially about the music. Kelly doesn't understand how things work in England," the Irishman added.
"She has to realise it's not all about the singing - likeability is number one. She's not used to being criticised either."
> Gary Barlow beats Kelly Rowland to be crowned best X Factor judge
> X Factor panel is divided, says Tulisa Contostavlos
Watch Digital Spy's interviews with the X Factor judges below: