Swiss trade unions say a new method of calculating salary differences between the sexes shows women are paid up to one fifth less for the same work.
Despite equal pay for equal work being enshrined in the constitution, the Swiss Federation of Trade Unions said there had been little progress over the past 25 years.
As part of a new campaign for higher pay for women, launched on Tuesday, the unions unveiled an online pay calculator.
The tool takes into account qualifications, including work experience and level of education, to evaluate salaries between men and women doing the same job.
In dozens of branches, the unions found differences in pay of between three and 21 per cent, after these factors were taken into account.
They said making the calculation tool available on the internet promoted transparency, empowering women to demand equal pay.
Many women were barely able to earn a living, the unions said, and their lower pay also meant many were unable to put money aside for a rainy day, or make adequate contributions to company pension plans.
Salary inequality also made it difficult for men and women to job share, since it rarely made economic sense for a mother to work and the father to stay at home to look after the children.
The unions pointed out that discrimination was not limited to unequal salary between men and women doing the same job.
They said it often started with the type of occupations considered either men or women's work.
swissinfo with agencies
The unions evaluated salary differences among employees working in 40 different branches.
Women's salaries are between 3% and 21% lower than men's.
Equal pay for equal work was enshrined in the Swiss constitution in 1981.