(CNN) -- Switzerland's largest city has permitted the use of controversial posters which call for a ban on the construction of minarets on mosques in the European country.
The Federal Commission against Racism said the posters defame Switzerland's peaceful Muslim population.
The posters are part of a campaign by the nationalist Swiss People's Party (SVP) and feature a veiled woman against a background of a Swiss flag pierced by several minarets resembling missiles.
The cities of Basel and Lausanne have described the posters as racist and banned them in publicly-owned spaces. However, Zurich is among a clutch of cities that have chosen not to prohibit them.
According to the SVP, the minarets symbolize ideological opposition to the country's constitution.
Switzerland will hold a national referendum on the issue on November 29.
According to Agence France-Presse, an opinion poll by the daily Tages-Anzeiger showed more than 51 percent of Swiss voters are against any ban on minaret construction.
The Swiss government and all the other major political parties are recommending a "no" vote, while local Christian, Jewish and Muslim leaders have joined forces to reject a ban, AFP added.
The mayor of Zurich, Corine Mauch, told CNN that the decision on the poster was taken on the basis of political freedom of speech in the run-up to November's vote.
"While we disapprove of the posters we took the decision after legal consultations.
"We consulted the Federal Commission against Racism and spoke to Muslim communities in the city, but decided banning the posters from public spaces would draw more attention to the issue." Do you agree with the Zurich decision?
However, the Federal Commission against Racism said in a statement Wednesday that the posters "defame Switzerland's peaceful Muslim population, feed prejudice, and portray the Muslim community as wanting to dominate Switzerland, oppress women and trample on fundamental rights."
The SVP have courted controversy with their campaigns in the past. In 2007 they faced international criticism for leading an anti-immigration campaign during the federal election that featured a poster with a white sheep kicking a black sheep off a Swiss flag.
Under party leader Christoph Blocher they went on to win the biggest share of the vote in the 200-member parliament, taking 55 seats.
Earlier this year they issued a poster depicting crows pecking at a map of Switzerland, as the country prepared to vote on whether to support an extension of a free movement of labor deal with the European Union which would include new members, Bulgaria and Romania.