The workers, members of the Unia and Syna unions, are demanding the preservation of retirement at age 60, better protection in case of bad weather and measures against using cheaper labour from foreign countries, known as “wage dumping”.
On Monday, 3,000 building trades workers downed tools in Italian-speaking Ticino and similar protests are planned at construction sites in French-speaking Switzerland (Suisse Romande) on Wednesday.
In a press statement the unions said the Swiss contractors' association was not taking their demands seriously.
A collective agreement for the sector expires at the end of the year but talks, launched months ago, have ground to a halt.
The contractors have collected 26,000 signatures from workers to support their position but the unions maintain that most of them were obtained under pressure.
The unions for their part have collected the support of 30,000 workers who have signed a petition demanding the two side return to the negotiating table.
The unions have stopped short of striking but they have threatened to so, something the employers have strongly objected to.
The contractors say they walked away from the bargaining table after raising concerns that unions were sending “inspectors” to work sites to check against “wage dumping”, Blick reported online.
Talks are scheduled from November 20th to 27th to discuss salaries for 2016, as well as early retirement plans, but the unions hope to be able to resolve the collective agreement dispute then, the ATS news agency reported.