People take part in the Women's March in Ajijic, Mexico - a city with a large community of U.S. and Canadian nationals - January 21, 2017.

Mexicans who help build U.S. President Donald Trump's planned border wall would be acting immorally and should be deemed traitors, the Catholic Archdiocese of Mexico said on Sunday, turning up the heat on a simmering dispute over the project.

In a provocative editorial, the country's biggest Archdiocese sought to increase pressure on the government to take a tougher line on companies aiming to profit from the wall, which has strained relations between Trump and the Mexican government.

"Any company intending to invest in the wall of the fanatic Trump would be immoral, but above all, its shareholders and owners should be considered traitors to the homeland," said the editorial in Desde la fe, the Archdiocese's weekly publication.

On Tuesday, Economy Minister Ildefonso Guajardo warned firms it would not be in their "interests" to participate in the wall. But the editorial accused the government of responding "tepidly" to those eyeing the project for business.