The so-called anti-burqa vote comes after years of debate in Switzerland following similar bans in other European countries -- and in some Muslim-majority states.
Women in Islamic full-face veils are an exceptionally rare sight in Swiss streets.
Even though the proposal to ban full facial coverings did not mention the burqa or the niqab -- which leaves only the eyes uncovered -- there was no doubt as to what the debate was about.
Campaign posters reading "Stop radical Islam!" and "Stop extremism!", featuring a woman in a black niqab, have been plastered around Swiss cities.
Rival posters read: "No to an absurd, useless and Islamophobic 'anti-burqa' law".
The ban would mean that nobody could cover their face completely in public -- whether in shops or in the open. But exceptions would include places of worship.
A 2019 Federal Statistical Office survey found that 5.5 percent of the Swiss population were Muslims, mostly with roots in the former Yugoslavia.
Government calls for a rejection of the ban
The government and parliament have opposed a nationwide ban.
Their counter-proposal -- which will automatically become law if the initiative is rejected -- would require people to show their faces to the authorities if necessary for identification.
Under Switzerland's system of direct democracy, any topic can be put to a national vote as long as it gathers 100,000 signatures in the wealthy country of 8.6 million people.
Rounds of votes take place every three months.
To pass, initiatives require support from a majority of voters nationwide, and from a majority of federal Switzerland's 26 cantons, six of which count as half-cantons in votes.
A 2009 Swiss referendum banned the construction of minaret towers on mosques.
