World Bulletin / News Desk

The woman's shadowed eyes stare out from a black niqab with the poster's tagline urging Swiss voters to reject "uncontrolled naturalisation."

"That is exactly what they are trying to (do)", said Pius Walker, who heads the Zurich-based advertising agency Walker AG.

"It is a very, very frightening thing that is going on here."

The issue in Sunday's vote, the latest in Switzerland's direct democracy system, is whether the grandchildren of immigrants should be able to benefit from an expedited citizenship process.

The government as well a majority of lawmakers and political parties support the proposal.

They argue that children born in Switzerland, who have a grandparent who was also born in the country or had a residency card, should be able to skip a few steps in the arduous process of securing a Swiss passport.

According to a migration department study, an estimated 25,000 people currently qualify as third generation immigrants, nearly 60 percent of whom are Italian.

But in campaigning against the measure, the rightwing nationalist Swiss People's Party (SVP) has made clear that Italians were not its primary concern.

"In one or two generations, who will these third generation foreigners be?" SVP lawmaker Jean-Luc Addor wrote in an opinion piece on the party's website.

"They will be born of the Arab Spring, they will be from sub-Saharan Africa, the Horn of Africa, Syria or Afghanistan," he warned.