A U.S. clothing industry group is urging the United States Trade Representative (USTR) to blacklist Alibaba Group Holding Ltd's popular Taobao shopping website for persistent intellectual property rights violations despite pledges by the e-commerce firm to curb the problem.

The American Apparel and Footwear Association asked the USTR to re-instate Taobao on its "notorious markets" list of physical and online marketplaces that reportedly engage in and facilitate substantial copyright piracy and trademark counterfeiting.

Taobao was put on the list in 2011 but removed in 2012 after it made efforts to address the concerns of intellectual property rights holders and committed to cut the amount of infringing listings.

But Juanita Duggan, President and CEO of AAFA, said in a statement late on Monday the piracy problem remained acute and AAFA members faced "enormous difficulty" working with Taobao to solve it.

"The sheer volume of counterfeits on the site as reported by our members, along with the company's unwillingness to make serious reforms is why, after three years, we feel it is necessary to recommend that Taobao be added back to the list and that the U.S. elevate the pressure on them to make substantive, measurable improvements to the counterfeit problem," she said.

The AAFA's submission to the USTR that follows "complaints regarding the slow, sluggish, and confusing systems" Taobao uses to process requests to remove listings for counterfeit products.

Alibaba said on Tuesday it was willing to discuss outstanding issues with the AAFA, but the group had refused to meet with it.

"To protect consumers, brand owners and legitimate sellers and to maintain the integrity of our marketplaces, we use and will continue to enhance a broad range of measures to prevent counterfeit and pirated goods from being offered and sold on our marketplaces," an Alibaba spokeswoman said in a statement.

The AAFA noted that it also called out several other marketplaces, both online and physical, including in China, Mexico, Uruguay, Thailand, Ukraine, Spain, Turkey, United Arab Emirates, India, and Vietnam.