Voters will have the final say on a CHF6 billion ($6.1 billion) package to buy new fighter jets for the Swiss airforce.
A committee made up of members of left-wing parties on Wednesday handed in the necessary signatures to trigger a vote on whether to overturn a parliamentary decision taken last December.
The pacifist Switzerland Without an Army group said it submitted just under 66,000 signatures to the Federal Chancellery.
They argue the price for the new jets - to replace the aging fleet of F/A-18 and Tiger aircraft by 2025 - is too high and the money should better be spent on education, public transport and the state old age pension system.
“It is an irresponsible purchase and a waste of money,” said Green parliamentarian Marionna Schlatter.
However, an alliance including centrist and right-wing parties as well as employers organisations, have dismissed the allegations, saying the new aircraft were needed to ensure Switzerland’s security, freedom and economic prosperity.
In 2014, voters rejected a plan to buy 22 Swedish Gripen jets from Saab for CHF3.1 billion, overturning a decision by the Swiss parliament.
The government has scheduled the latest vote for September 27 alongside four other issues, including a right-wing proposal to scrap a deal with the European Union on the free movement of people, which has been in force since 2002.
The collection of signatures and nationwide votes - a key element of Switzerland’s system of direct democracy - were suspended until the end of May due to the coronavirus pandemic.