More than 14,000 people took part in the traditional May 1st parade in Zurich, the country’s largest city, broadcaster RTS reported.
Christian Levrat, president of the Swiss socialist party, headed the procession ahead of a banner reading “good work — minimum wage”, the broadcaster said.
Levrat addressed participants with a speech in which he raised concerns about the impact of the February 9th referendum vote in favour of restricting immigrants.
He warned of the dangers of a “reactionary” Switzerland abandoning “our humanitarian tradition” and of a “suicidal isolationist policy in Europe”.
Although the procession was peaceful, merchants in the centre of Zurich prepared for a more violent counter-demonstration by barricading shop front windows as early as Wednesday, RTS said.
Similar marches were held in Basel, Bern and Geneva, which each attracted around 1,500 participants, as well as cities such as Lausanne, Fribourg and Olten in the canton of Solothurn.
Unions led the call to back the proposed minimum wage.
Voters go to the polls on February 18th on what would become the world’s highest minimum pay at 20 francs ($22.75).
The government and business groups are opposed to the proposal, saying it could jeopardize the country’s economic future.
But Bernadette Häfliger Berger, of the Syndicom union, told Labour Day marchers the minimum wage would no more lead to jobs cuts than other social benefits, the Berner Zeitung newspaper said.
The newspaper said some demonstrators clad in black and wearing masks chanted revolutionary slogans, although there were no initial reports of trouble.