MEXICO CITY (AP) — The Mexican government said Tuesday it has agreed to review a labor complaint filed by the United States under the U.S.-Mexico-Canada free trade pact.

The complaint filed earlier this month said workers’ rights to freely choose their union may have been violated at a Panasonic Automotive Systems factory in Reynosa, across the border from McAllen, Texas.

Mexico’s Economy Department said in a statement it would meet with the parties in the dispute to determine if there were any violations of labor codes.

Activists say that even though employees at the plant voted in April to join an independent union, the company continues to work with the old union.

All three of the U.S. labor complaints filed against Mexico so far under the trade pact involve Mexican workers’ efforts to replace old-guard unions that have long signed contracts behind workers’ backs and kept wages low.

In April, workers at the Panasonic Automotive Systems factory voted overwhelmingly to be represented by a new union.

Employees at the maquiladora, as the border plants are known, had long been represented by a union affiliated with the Confederation of Mexican Workers.

The new Independent National Industrial Union of Mobility Services won with 1,200 votes to 390 for the old union.

But the company has not respected that decision, said Susana Prieto, a federal congress member who is a lawyer and labor activist.

“Even though they chose a union, the company continues to work with the ‘protection’ union that they got in against the workers’ wishes,” Prieto said.

Calls to Panasonic Mexico’s headquarters for comment went unanswered.

Mexico has recently adopted laws saying employees have a right to vote by secret ballot on contracts and union representation.

In February, in another border city, Matamoros, employees at a U.S.-operated Tridonex auto parts assembly plant in Matamoros, across the border from Brownsville, Texas, overwhelmingly voted to have an independent union represent them.

Workers at a GM plant in the northern Mexico city of Silao voted to oust the old-guard Confederation of Mexican Workers and replace it with an independent union.

Such votes, while still scattered and few in number, could eventually stem the outflow of U.S. manufacturing jobs to Mexico, as it becomes harder for employers to guarantee low wages by signing contracts with the old-guard Mexican unions. Many Mexican workers make 10% to 15% of wages for similar jobs in the U.S.

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