(Reuters) - Italy's competition authority (AGCM) said on Wednesday it had started an investigation into luxury fashion groups Armani and Dior over the alleged exploitation of workers in their supply chain.

Milan prosecutors ordered several Chinese-owned firms that are based in Italy and that produced luxury goods for Dior and Armani to be put under administration. The prosecutors had accused the companies of systematically abusing their employees.

In a statement, AGCM said its probe focused on some companies of the Armani Group and some companies of the LVMH-controlled Dior Group, adding that it had acted in response to the actions by the Milan prosecutors.

"The (Armani and Dior) companies may have made untrue ethical and social responsibility claims, in particular with regard to working conditions and compliance with legality at their suppliers," the antitrust agency said.

They were placed under investigation "for possible unlawful conduct in the promotion and sale of articles and clothing accessories, in breach of the (Italian) Consumer Code," it added.

Armani and LVMH did not immediately respond to requests for comment.