Ms Brabin was raising a point of order in the Commons on Monday about Downing Street's decision to order senior journalists from some of the UK's major news organisations to leave before a briefing on Boris Johnson's Brexit plans when she spoke at the despatch box wearing the outfit.
A Twitter user shared a photograph of her and asked: "Is this really appropriate attire for Parliament?"
But many of the responses were less polite, and Ms Brabin replied to the tweet: "Sorry I don't have time to reply to all of you commenting on this but I can confirm I'm not....
"A slag, hungover, a tart, about to breastfeed, a slapper, drunk, just been banged over a wheelie bin.
"Who knew people could get so emotional over a shoulder..."
Ms Brabin appeared on BBC Breakfast this morning to address the saga, which she branded as “everyday sexism”.
She said: "You can’t take on the world if you’re always worried about whether your hair’s right or not.
“Listen to what we say, not what we wear."
But she did admit she was “startled” by the “vitriolic nature” of the comments.
She added: “It’s part of the territory as a politician. I am in a privileged position that I can brush this off.
"But I feel that it’s my responsibility to call it out for women who don’t have that amplification.
“Because there are women around the world that are putting up with this day in, day out, where they’re being demeaned for what they wear.
“It’s another case of everyday sexism.”
And she added her predecessor as Shadow Culture Secretary Tom Watson would not have faced the same criticism.
She said: "There’s lots going on about the BBC and the future of the BBC and shoulders seem to take precedence."
Speaking of the people who commented online she added: “They are anonymous people often, keyboard warriors often sat in their mum’s back bedroom eating Pot Noodles having a pop at people they don’t know anything about.”