Millions of people throughout Mexico are threatening to turn their backs on US products and businesses on May 1 as part of a protest that is being dubbed “the great American boycott”.

Teachers, telephone operators, housewives and farmers are just a handful of the groups that have decided on the boycott as a way to support Latin Americans living in the US who have vowed not to turn up to work on May 1.

The protest in the US, called “a day without immigrants”, aims to put pressure on Congress to legalise the status of millions of undocumented migrant workers who have become a vital source of cheap labour for the US economy. Senators have been debating several proposals to reform immigration laws but have failed to reach a compromise.

The delay has led to increasing frustration among the Hispanic community in the US, and now it is starting to spread across the border.

In Mexico, by far the biggest source of cheap labour for companies in the US, the boycott is threatening to turn into a nationwide movement. Fernando Amezcua, a high-ranking official at the Mexican Union of Electricians (SME), says his organisation will raise the issue at its general assembly on Monday with the idea of urging its 60,000 members to participate in the protest.

He also says the SME is calling on a wider coalition to support the boycott, which he claims brings together about 10m members of unions, social groups and non-governmental organisations.

On the streets of Mexico City, the word is spreading. Cristina Robles, an elegantly dressed business woman who has just done the family shopping at Superama, a supermarket chain owned by US retailer Wal-Mart, says she will support the ban. “I am not going to buy anything American,” she says. “I know it is not easy because there are a lot of illegal immigrants but the US has to treat them the same as any other worker.”

Joaquín García Nava, owner of a corner cafe in La Condesa, a swanky neighbourhood in central Mexico City, agrees. “For me, the protest serves a double purpose: I get to support the immigrants and I also get to express my slightly anti-Yankee sentiments.”

In other regions, too, what started out as a grassroots initiative spread through e-mails is catching on. In Jerez, a town of about 60,000 in Zacatecas, a largely agricultural state to the north of the capital, residents have staged a number of demonstrations in parallel with those that have taken place in recent weeks throughout the US.

Antonio Pereyra, a local government official, says people feel strongly about the need for immigration reform in large part because of their increasing dependence on remittances – money sent home by immigrants in the US. “Every single family has at least one member working in the US and without the money they send back home every month many would not be able to survive,” he says.

According to Mexico’s central bank, the estimated 7m Mexicans living and working illegally in the US send their families back home more than $20bn (€16.28bn) a year, making remittances Mexico’s second-biggest source of foreign currency after oil.

Larry Rubin, who heads the American Chamber of Commerce in Mexico City, a body that represents US companies in Mexico, is sympathetic to those who are pushing for progressive immigration reform. But he argues that boycotting US products and businesses in Mexico is misguided. “It is totally the wrong approach because the US business community has been one of the most adamant supporters and lobbyists of a comprehensive immigration bill.”