Trade unions say a proposed reform of the unemployment insurance scheme unfairly exempts high salary earners and undermines social cohesion.
Paul Rechsteiner, president of the Swiss Trade Union Federation said top earners should contribute according to their income to shore up the insurance, which has run up debts of about SFr7 billion ($6.7 billion).
He said the proposed reform, which comes to a nationwide vote on September 26, was unjust and its supporters, including the government, were using misleading information.
Other union representatives said that cuts of SFr620 million in insurance payments put the burden on the younger generation, those over the age of 55 and employees with health problems.
On Monday supporters of the reform, from centre-right and rightwing parties, said rejection of the reform would lead to a 0.5 per cent increase in salary deductions to fund the insurance.
Parliament approved the reform in March, but centre-left parties and trade unions collected enough signatures to force a referendum on the issue.
Urs Geiser, swissinfo.ch