MEXICO CITY — Canadian Prime Minister Justin Trudeau raised the issue of Mexico’s persistently low wages during a visit Friday, as both countries and the United States continue negotiations over the North American Free Trade Agreement.

In a speech to the Mexican senate, Trudeau said support for NAFTA “depends on the fruits of this trade being fairly shared.”

“So we must pursue trade agreements that are win, win, win, helping workers across North America achieve better standards, wages and working conditions,” he told lawmakers.

Mexican wages are a key element in NAFTA talks, with Washington pushing to increase labor protections and pay. Auto workers in Mexico, for example, often earn about $2 per hour compared with $30 or more by their counterparts in the other two countries.

Wages are kept low in Mexico in part because of antiquated labor laws and pro-government unions that often sign contracts behind workers’ backs. Some unions are so absent from the workplace that employees sometimes don’t even know one exists.

It was not clear whether Trudeau and Mexican President Enrique Pena Nieto discussed the wage issue directly during the Thursday and Friday visit.

Pena Nieto said Thursday night at a dinner for Trudeau that “Mexico sees the renegotiation of NAFTA as a way to ensure that any agreement reached represents an opportunity to improve labor conditions in Mexico.”

“Mexico doesn’t want to be competitive based on low wages,” Pena Nieto said. “Mexico wants to compete on the basis of skilled labor.”

However his government has not moved to get rid of thousands of pro-company “protection” contracts that prevent real unions from organizing. And leaders of crooked labor federations are in many cases members of Pena Nieto’s Institutional Revolutionary Party, or PRI.

Trudeau said improving labor standards may be the only way to protect the 23-year-old trade pact.

“Progressive labor standards are how we ensure that a modernized NAFTA will also bolster not just free and fair trade, but will enjoy long-lasting popular support,” Trudeau said.