The rightwing Swiss People's Party says it has collected over 170,000 signatures in three months for its initiative to expel foreign criminals.
The proposal has caused controversy at home and abroad in particular for its accompanying "black sheep" poster campaign, which has been accused of racism, depicting three white sheep kicking a black sheep out of the country.
The initiative calls for any foreigner condemned of murder, rape, robbery, drug trafficking, burglary, human trafficking or social security abuse to have their residence permit taken away. Once thrown out of the country, they cannot return for up to 15 years, or even 20 if they re-offend.
Under the Swiss constitution, the campaigners have 18 months - until January 2009 – to collect at least 100,000 signatures from citizens to force a nationwide vote.
At a news conference in the capital, Bern, on Monday the People's Party thanked other Swiss political parties for their criticism of the initiative, which they said had increased public attention.
The poster will go down in People's Party history as one of the most effective ever used, said People's Party parliamentarian Toni Brunner.
"Attacks similar to those made by the United Nations' special rapporteur on racism, Doudou Diène, and the Swiss president, Micheline Calmy-Rey, had increased by four or five the number of signatures," said Brunner.
In August Calmy-Rey denounced the "black sheep" posters as "irresponsible" and liable to incite racial hatred, while Diène called on the party to withdraw them and sought explanations from the Swiss government.
The People's Party provocative campaign and immigration plans and build-up to the October 21 elections have also recently captured media attention across the world.
A week ago police clashed with several hundred leftwing militants who stopped a march of supporters of the People's Party which had been trying to hold a pre-election rally outside the parliament building in Bern.
Brunner took a swipe at the foreign press, which he claimed had been guilty of writing critical articles "directed by the left and some of which were completely false".
At the news conference, Ueli Maurer, president of the People's Party, refused to answer questions posed by a foreign journalist.
"I don't give interviews to foreign journalists; I want to win the elections in Switzerland," he said.
In related news, a legal complaint by the Communist Party over the "black sheep" poster has been rejected.
The justice authorities in Zurich said they had suspended an investigation because xenophobia and racism were two separate issues.
Further complaints are pending in other cantons.
swissinfo with agencies
Parliamentary elections are scheduled for October 21. Both chambers of parliament will choose the new seven-member cabinet in December.
The rightwing Swiss People's Party is one of four governing parties. It won nearly 27% of the vote in the 2003 elections to the House of Representatives.
This year's election campaign has been dominated by the People's Party, its controversial justice minister, Christoph Blocher, and the party's hard-line stance on immigrants and foreigners.
Swiss People's Party and foreigners
Recent policies of the rightwing Swiss People's Party with regard to foreigners in Switzerland include:
Foreign residents who commit crimes in Switzerland should be expelled after serving their sentences. If they are minors, the parents should be expelled with them.
The construction of minarets – the traditional tower of a mosque – should be forbidden in Switzerland.
When foreign residents of a commune want to acquire Swiss citizenship, the commune should continue to have the right to put their applications to a popular vote.
Foreigners who do not learn the language of the area in which they are resident must leave the country.