MEXICO CITY A labor dispute mechanism under the U.S.-Canada-Mexico (USMCA) trade deal does not apply at Grupo Mexico's San Martin mine in Zacatecas state where the U.S. had raised concerns over alleged worker rights abuses, Mexico said on Tuesday.

Mexico's rejection of a U.S. complaint filed in June marks one of the few times since the USMCA went into effect in 2020 that it has deemed a case ineligible for review under the pact.

The concerns flagged by the U.S. are being addressed in Mexico's court system with a final outcome expected soon, Mexican officials said.

U.S. labor and trade officials, as well as Grupo Mexico, did not immediately respond to requests for comment.

The U.S. government on June 16 had asked Mexico to review the matter, citing a request from two major U.S. labor organizations and a Mexican union known as The Miners.

The groups argued that Grupo Mexico's operations at the San Martin mine, which contains lead, zinc and copper, violate a strike that began in 2007, and that the company has bargained with employees who did not have the right to formally represent the mine's workforce.

Grupo Mexico pushed back against those allegations, saying it legally resumed operations with the approval of workers in 2018.

Mexican officials said both these events pre-date the USMCA, putting it out of reach of the trade deal's dispute process, including a tool known as the Rapid Response Mechanism intended to quickly resolve labor abuse allegations.

A Mexican court ruled in favor of the workers' union in June, ordering Grupo Mexico to pay back wages and benefits.

"It will be resolved in the Mexican judicial system," Mexico's economy and labor ministries said in a joint statement.

(Reporting by Daina Beth Solomon and Kylie Madry; Editing by Sarah Morland and David Gregorio)