Barber recreated the clip in multi-coloured bikini bottoms, even nailing the hip twist Ratajkowski pulls off on her shoot.
But it's the Australian comedian's caption that has left many of her 8.4 million followers furious.
"We are sick of you objectifying our bodies! Also, here's my ass," Barber wrote.
The onslaught of criticsism has been thick and fast, with many describing the caption as "missing the mark" and accusing it of being an example of internalised misogny.
News.com.au has contacted Celeste Barber for comment.
"Pretty sad to see this caption. As women we can rage against being sexually objectified by men and the market AND also choose to (re)present our bodies in a sexual way," one said.
"I think you sometimes oversimplify what is going on and your 'light hearted' jabs cross the line into an old school anti-sex feminism and end up shaming women," another wrote.
While one argued: "This caption and many of the comments here are disappointingly misogynistic. How a woman chooses to use her own body, sensuality and sexuality is entirely up to her. Hating on other women for how they choose to do so is harmful."
Others used the post to implore women to "stop tearing each other down".
"Tried so hard to be a feminist you've circled back around into misogyny. this is embarrassing. your whole schtick is putting down women while pretending to be quirky and make fun of yourself. do better," one stated.
"Both of these things can be true. This is such a disappointing and cheap caption, Celeste," another agreed.
Another woman said: "This captions reeks of people who tell women 'what did they expect' when they go out in a short skirt and get sexually assaulted... please check your internalised misogyny..."
Ratajkowski has yet to address the backlash since it erupted on Tuesday following the post.
Not everyone was offended by the parody, with TV host Sophie Monk and UK reality star Louise Thompson both commenting with a series of laughing face emojis.
"Hilarious," one user commented, while another stated Barber was "my queen".
In August, Barber was called out by one of her parody subjects for using her content without her consent.
Portuguese model Anastasia Young's video showing her doing an interpretative dance on the beach holding a ball became the subject of one of Barber's comedy sketches.
But when Young commented, Barber clapped back, sarcastically writing: "Oh sh*t sorry. Can I please use this public video to post on this public platform?"
