Rightwing politicians have launched a campaign against government plans to step up military cooperation with overseas forces. The populist parliamentarian, Christoph Blocher, said the proposals were a veiled attempt to take Switzerland into Nato.
Launching the campaign on Friday, opponents of planned new army laws said they were in breach of Swiss neutrality and the country's long-standing humanitarian tradition.
Their aim is to persuade Swiss voters to reject the changes, when the issue goes to a nationwide vote in June.
Speakers, including Blocher, accused the government of surreptitiously trying to lead Switzerland into Nato and to turn the Swiss militia army into a professional army.
The amended law foresees the stepping up of cooperation and training between Swiss troops and other armies, and would allow Swiss soldiers to be fully armed when serving in international peacekeeping missions abroad.
The law does not permit combat missions, and participation for individual soldiers would be on a voluntary basis.
In an emotive appeal, the campaigners said the SFr100 million ($59 million) earmarked for international military cooperation should be used for humanitarian purposes instead.
Leftwing groups are also opposed to the new law, and have collected enough signatures to force a referendum on the issue.
Parliament and the government are both in favour, and the defence ministry plans to launch its campaign to drum up public support in the next few days.
In 1994, Swiss voters rejected a proposal allowing Swiss troops to take part in peacekeeping missions under the auspices of the United Nations.
There are currently 160 mainly unarmed Swiss army volunteers taking part in the Kfor peacekeeping mission in Kosovo. Their mandate runs out at the end of this year.
Switzerland has also provided military personnel and experts for international missions in Bosnia-Herzegovina, as well as in several African countries, the Middle East and Asia, including for the Neutral Nations Supervisory Commission on the Korean border.
swissinfo with agencies