The former band's frontman revealed that he is upset that he is blamed for the group's split, after Noel claimed their demise began after Liam was too hungover to perform at 2009's V Festival.
"Those are big lies that I've got to clear up, the first one about me being hungover - I got diagnosed with laryngitis for the V Festival, wasn't hungover," he told BBC Radio 1.
"I do gigs when I've been hungover, I'm a big boy. I'm not going to cancel a gig because I've got a headache."
Addressing rumours that the split was over advertising for Liam's Pretty Green clothing line, he insisted: "Them words, Pretty Green, have never come out of my mouth [to] Noel Gallagher. Ever.
"So all this about him saying I tried to get Pretty Green in an advertisement or Oasis tour programme is absolute s**t, saying it was the demise of Oasis, I'm not having it.
"He needs to know there's two to blame for Oasis splitting up and one of them is sitting here right now talking, and the other one's Noel Gallagher," he continued. "It's time he woke up man, he's no angel. He's breaking my heart."
Liam, who now fronts rock band Beady Eye, also insisted that he would fight his brother "verbally, physically, musically and mentally" over his claims, adding: "I don't play games. Competition is for idiots. As long as we are taking care of our business, we'll roast anyone."
Noel recently announced news of his new band and album, called Noel Gallagher's High Flying Birds, which is released in October.
Watch Noel Gallagher's recent press conference below: