As part of US ratification of the United States-Mexico-Canada Agreement (USMCA), Democrats in Congress proposed designating up to five American labor attaches to monitor compliance in Mexico.
Mexico rejected on Saturday an attempt in the US Congress that would send American inspectors into Mexican factories to ensure they respect labor protections provided by the new North American trade pact.
The Senate in Mexico City ratified the trade pact on Thursday, after more than two years of arduous negotiations with Washington and Ottawa.
Jesus Seade, the chief Mexican trade negotiator on the accord, told reporters Saturday that while most of the proposed US legislation was in line with expectations, the proposal for labor inspectors was not part of the agreement the three countries signed in Mexico City last Tuesday.
"For evident reasons," he said, Mexico was not consulted about that provision.
Seade, Mexico's Undersecretary for North America, said he had raised the matter with US Trade Representative Robert Lighthizer and would travel to Washington on Sunday to consult with members of Congress.
Under Mexican law, he said, American officials "can in no case have inspection powers" in Mexico.
The new pact, which replaces the 25-year-old North American Free Trade Agreement (NAFTA), was first signed in November 2018.
But it soon bogged down in political complications, particularly in the United States, where Democrats questioned whether it would really force Mexico to deliver on labor reforms meant to level the playing field between lower-wage Mexican workers and their better-paid American counterparts.
After additional talks, the pact signed on Tuesday includes tougher enforcement of labor provisions. Changes include a minimum-wage requirement for workers in the automotive industry, to be phased in over five years.
The additions won the blessing of House Speaker Nancy Pelosi, the Democrat needed to move the agreement forward in Congress, as well as the largest US labor federation, the AFL-CIO.
US negotiators originally proposed sending inspectors to monitor Mexican compliance, but the Mexican government rejected that approach. Instead, the three countries agreed to create mediation panels to resolve any complaints.
US President Donald Trump, who triggered the trade pact's renegotiation in 2017, argued that NAFTA was a "disaster" for American workers.