(Reuters) - Amnesty International UK said on Tuesday Shein's potential London initial public offering would be a "badge of shame" for the London Stock Exchange ( LDNXF ) because of the fast-fashion firm's "questionable" labour and human rights standards.

Shein confidentially filed papers with Britain's markets regulator in June, two sources told Reuters on Monday, kicking off the process for a potential London listing later this year.

"Rewarding Shein's current methods via a flotation would be a badge of shame for the London Stock Exchange ( LDNXF )," Dominique Muller, an Amnesty International researcher specialising in the garment industry, said in a press release.

Shein did not immediately respond to Reuters' requests for comment. LSEG declined to comment.

Shein has previously said it is investing in strengthening governance and compliance across its supply chain.

Shein's listing plans had run into political opposition in the United States over labour concerns.

The China Securities Regulatory Commission (CSRC) earlier this year informed Shein the regulator would not recommend a U.S. IPO due to the company's supply chain issues, Reuters has reported.

Shein executives recently met with Amnesty representatives and subsequently responded in writing to a series of human rights related questions, Amnesty International said.