The Social Democrats are against Sunday shopping and for a moratorium on genetically modified organisms, issues which will go to a nationwide vote in November.
At a conference on Saturday, Switzerland's second largest party also launched a referendum against tightening asylum legislation, due to be discussed by parliament in the autumn.
Hans-Jürg Fehr, the party president, stressed that the proposed amendments relegated Switzerland's humanitarian tradition to the scrapheap.
The Swiss are due to decide in November whether to amend labour laws to allow shops at airports and railway stations to open on Sundays and if a moratorium on GMOs in agriculture lasting five years should be allowed.
Delegates in Rapperswil were unanimous in their support for the GMO moratorium and the majority were against the extension of opening hours.
In his speech, Fehr said that the party was confident that Switzerland would vote yes to the free movement of persons from the new European Union states on September 25.
He criticised the cabinet's recent swing to the right, which he said was apparent in moves to tighten asylum policy and attempts to export weapons to Iraq and Pakistan.
Earlier this year, the cabinet announced its decision to send surplus Swiss army tanks to Iraq. It was later forced to backtrack, after attracting flak from parliamentarians.
However, Fehr said that his party would remain on its guard, as the delivery could still take place, and it would bring up the issue when parliament was in session again.
He added that the climate in parliament had deteriorated, making it almost impossible for the Social Democrats to find support among other parties for its positions.
He reiterated the party's goal of gaining an extra cabinet seat at the expense of the centre-right Radical Party at the next parliamentary elections in 2007, when he predicted the Social Democrats would emerge as the strongest party in the polls.
At Saturday's conference the party also called for student fees to be abolished and a general improvement in conditions for undergraduates.
swissinfo with agencies
The Social Democrats have 38,000 members, and are represented in every Swiss canton.
The party has 52 seats in the House of Representatives - four fewer than the Swiss People's Party, the largest in parliament - and nine seats in the Senate, as well as two of the seven cabinet posts.
The Social Democrats met in Rapperswil, canton St Gallen.
Delegates took position on two issues set to be voted on by the public in November.
They opposed the Sunday opening of shops in airports and railway stations and voted in favour of a five-year moratorium on GMOs in agriculture.