The People’s Party (SVP), which takes a hardline stance on immigration and opposes closer ties with the EU, said it had created a national committee tasked with pushing the ‘No’ campaign.

"The group’s aim is to secure a no vote to the undemocratic and unconstitutional ‘package’ put to vote by the parliament," it said in a statement.

While Switzerland is not a member of the European Union, it has a number of bilateral agreements with the 27-member bloc on issues such as free trade and labour.

Swiss voters will go to the polls on 8 February to decide whether to extend the right to work in Switzerland to citizens of new EU members Bulgaria and Romania.

The SVP, which enjoys the support of one-third of Switzerland’s electorate, argues doing so will lead to an increase in immigration and that the country is already struggling to cope with present levels.

"All the workers from these countries can enter Switzerland freely under the pretext of looking for a job here. It is then almost impossible to check what they are up to," the SVP said.

"We are ready to bring an end to rising immigration which brings no real benefit to Switzerland," the SVP added.

The far-right party argues relaxing immigration rules will simply put pressure on salary and unemployment levels.

"Especially in a time of (economic) crisis, this pressure could have disastrous consequences for social security. We cannot accept that,"

All other political parties in Switzerland support a ‘Yes’ vote.

Brussels has warned that a failure to extend the free movement principle to Bulgarians and Romanians could jeopardise the country’s membership to the open-border Schengen Area, which allows passport-free travel between 25 European countries.

The Swiss People’s Party drew allegations of racism during last year’s election campaign after publishing a provocative poster showing three white sheep kicking a black sheep off a Swiss flag.

[AFP / Expatica]