Roberto Cavalli has accused Michael Kors of "copying everything".
The Italian designer is known for speaking his mind and has taken pot shots at Giorgio Armani and Dolce & Gabbana in the past.
Kors is the latest designer to be in the firing line, with Cavalli scathing in his critique of the American star's talent.
"Mr. Michael Kors, he copies everything!" he told Haute Living Miami magazine, according to The Hollywood Reporter.
"It's really a scandal and nobody has the courage to say anything. It's really not fair."
Kors recently showed his Fall/Winter 14 line at New York Fashion Week. It took in taupe and grey shades, with blouses and calf-length dresses the big looks, as well as well-cut coats. The designer discussed his desire to dress real women and was praised for coming up with looks that suit the modern female.
Despite his irritation with Kors, Cavalli insisted high street versions of catwalk looks are to be expected.
"Now, you have designers and you have Zara, which is meant to be fast and sold at a very cheap price, so you expect [copying]," he said.
Although he has built his career on his high-end designs, which often boast bold prints, Cavalli expressed his concern about people who obsess about the catwalk. He insists labels shouldn't be what makes a person buy a piece, rather it should be about what suits a woman's figure and makes them feel good.
It's not just Kors who Cavalli is dissatisfied with. He believes the fashion industry as a whole could do with a shake-up.
"Fashion is just about money now. There's no evolution. In the 18th and 19th centuries, fashion used to completely change every 20 years. Totally new silhouettes, etc. Now, there is less creativity. There's been nothing truly new since the 1950s, except many sneakers," he said.