Banning the construction of minarets is more likely to serve the cause of religious fanatics than to halt extremism, the Swiss justice minister said on Thursday.
Eveline Widmer-Schlumpf told a news conference in Bern that banning minarets would infringe basic human rights and endanger religious peace.
A nationwide vote on the issue is to be held on November 29.
"Such a ban would clearly run counter to the basic values of the Swiss state, and would be incompatible with the fundamental rights and principles laid down in the constitution," Widmer-Schlumpf said.
Freedom of belief does not only protect a believer's religious convictions, but also the right to proclaim them, she explained.
She added that the ban would be discriminatory against Muslims, since other religious communities would not be affected.
"We demand that the Muslims of Switzerland should respect our system of law and society," she said. "If we expect this of Muslims, we must also treat them in the same way as everyone else living in the country as regards religious freedom."
Widmer-Schlumpf was supported by Thomas Wipf, chairman of the Swiss Council of Religions, and Jean Studer, chairman of the government of canton Neuchatel.
The anti-minaret initiative was proposed by members of the rightwing Swiss People's Party and a small ultra-conservative Christian party, to counter what they describe as "creeping Islamicisation".
swissinfo.ch and agencies