The campaign against a SFr1 billion ($800 million) Swiss contribution to countries in eastern Europe is gathering pace.
The rightwing Swiss People's Party, which forced a nationwide vote on the issue scheduled for November 26, said on Monday the payment could prompt further financial demands from the European Union.
Party President Ueli Maurer warned that Switzerland could incur unpredictable costs if voters approved a pledge by parliament and the government to spend SFr1 billion for closer economic cooperation with ten new EU member states mainly in eastern Europe.
He said the Swiss contribution meant wasting money abroad without getting anything back in return. Maurer also dismissed suggestions by supporters of the payments that Brussels could torpedo bilateral negotiations with Switzerland if voters rejected the contribution.
So far Switzerland and the EU have concluded a total of 16 bilateral accords, on issues including trade, labour, transport, security, customs and taxation, and are currently preparing negotiations for deals on agriculture and closer scientific cooperation.
Maurer argued that his party, which is known for its anti-EU stance, was not against the so-called Cohesion Fund in principle.
But he insisted that the SFr1 billion contribution had to be compensated fully from the budgets of the foreign and economics ministries.
The People's Party also wants assurances that any possible Swiss payments to new EU members, including Bulgaria and Romania, are automatically put to a nationwide vote.
Two weeks ago the cabinet launched its campaign, saying the SFr1 billion is a good investment that will benefit not only the new EU states but also Switzerland.
The funds, to be spent over the next ten years, are to be used on projects, including education, trade promotion and environment, according to the government. The money is paid directly to the projects and does not go the EU Cohesion Fund in Brussels.
Sixty per cent of the SFr1 billion is to come from the budget of the foreign and economics ministries, while the remaining 40 per cent is taken from the regular budget of the federal administration.
A majority in parliament endorsed the contribution last March and three of the four main parties have also come out in favour.
However, the People's Party challenged the decision to a referendum by collecting the necessary signatures to force a nationwide vote.
In another development, the People's Party has recommended a no vote to a proposal for a unified child benefit system which will also come to a nationwide vote on November 26.
swissinfo with agencies
Switzerland has been granting financial aid to countries in eastern Europe to help them transform into market economies.
As part of the second set of bilateral treaties with Brussels, non-EU member Switzerland pledged to provide SFr1 billion to ten new EU member states mainly in eastern Europe.
Under the accord, almost half the funding will go to Poland. Hungary will benefit to the tune of SFr131 million, while the Czech Republic will receive SFr110 million.
The EU's Cohesion Fund is a structural instrument that has helped member states reduce economic and social disparities and stabilise their economies since 1994.
The funding will come mainly from cuts in aid programmes run by the foreign and economics ministries.
Breakdown of Swiss contribution to EU cohesion fund in Swiss francs:
Czech Republic: 109,780,000