Nicole Appleton claims she has only ever witnessed The Rock 'n' roll siblings have verbal fights, and insists her Battles with her sister Natalie - who she was in the pop group All Saints with - can be worse.
In a joint interview with Liam on Canadian TV show 'George Stroumboulopoulos Tonight', she said: "I've never really witnessed anything between Liam and Noel ... maybe phone arguments. But he has witnessed Nat and I fight."
Nicole - who is currently presenting TV talent show 'Cover Me Canada' - insists the pressure of being in a band with a sibling intensifies every problem or disagreement you may have.
She added: "The pressure of everything builds up. It's never anything serious that you fight over. These wars get built up over nothing. All the travelling and everything else really sends you a bit mad."
Noel quit Oasis in August 2009 after a backstage argument between the pair ended in Liam attacking his older brother with a guitar.
Since the split, the brothers have not spoken and Liam has formed a new band Beady Eye with the other ex-members of Oasis, while Noel has launched a solo project, Noel Gallagher's High Flying Birds.
Both have spoken about reuniting in 2015 for the 20th anniversary of their seminal album '(What's the Story) Morning Glory?'.