The former Australia's Got Talent judge came under fire for comments he made to his 232,000 Twitter followers about domestic violence.
"Men who hit women are pathetic. Women who make excuses and stay with the guy are just as bad," Brian tweeted on Saturday.
The controversial tweet sparked a heated series of tweets calling the 32-year-old Irish star out on his lack of the complexities of abusive relationships.
"Wow. Well you clearly have no understanding," one critic wrote.
"There should be no excuse for violence," Brian responded.
"@BrianMcFadden, er, except they're not hitting anyone. Luckily legal system doesn't share your view," another follower wrote back.
Author Tara Moss and Seven Network journalist Nick McCallum were among a barrage of critics outraged by the tweet.
"Speaking to domestic violence victims will change your mind. They live in fear and suffer emotional, financial insecurity," Nick wrote.
Brian apologised after seeing the backlash his comment had caused.
"Sorry if my last tweet upset anyone," he wrote. "It's just that one of my friends is in that situation and it made me angry."
Feminist writer Eva Cox told Fairfax that Brian's comment was "immature" and "silly".
"Domestic violence is very complex and women in those circumstances are told it's their own fault, they get convinced they're inadequate, ugly, and made to feel guilty," she said.
"We need to support the women and say it's not right and you're not the cause of it."
Domestic violence in Australia claims the life of one woman every week. One in three women over 15 years of age will report physical or sexual violence during their lives. For more information, visit the White Ribbon website, Australia's campaign to stop violence against women.
In pics: Brian McFadden's foot-in-mouth moments