"This dress that I did not design, I actually bought, is not a corset it's just fabric on the front," she said in a video.
"So, I think it's really cute, I bought it from a designer and it's just fabric people, it's not a real corset."
She also tweeted: "I would never put my daughter in a corset! Relax it's a dress I bought that is fabric that laces up and looks like a corset!"
Corsets are designed to sexualise the female body and are often worn by burlesque dancers - and many social media users say the item is inappropriate for a child so young. The clothing cinches a woman's waist to make them look smaller and enhance their bottom.
Kim herself has advertised waist trainers, a type of corset, on social media, and credited them with helping shape her hourglass figure.
Doctors, however, have warned against waist trainers and pointed out that they could cause serious damage to internal organs.
In North's case, social media users were outraged that Kim and Kanye could let their four-year-old daughter step out of the house wearing such an adult garment.
As photos of North wearing the corset began circulating on Instagram, some users slammed the outfit in concerned comments.
"This is a mess", one person wrote next to the pictures. "Why is this baby wearing a corset?"
Someone else worried that the outfit might attract sexual predators, while some called the accessory "ridiculous" on a little girl.
