Trade unions and centre-left political parties opposed to a planned reform of the state-run unemployment insurance have enough support to force a nationwide vote.
They gathered more than 140,000 signatures in support of a referendum against the changes – nearly three times more than are needed – which they handed in to the federal chancellery on Tuesday.
“The number of signatures is a clear sign that the issue is very much on people’s minds,” said Renzo Ambrosetti of the Unia trade union.
Under the plan, approved by a majority in parliament in March, daily allowances would be reduced and eligibility to payments limited.
Regular contributions by employers and employees to the insurance scheme would also be slightly raised.
Opponents say the reform unfairly punishes young employees and those over the age of 55.
However, supporters of the reform argue stricter measures are necessary to contain the rising debts of the insurance scheme which totalled SFr5.6 billion ($ 5.3 billion) at the end of last year.
The vote is scheduled for September 26.
Urs Geiser, swissinfo.ch