Voters in Switzerland have approved a proposal to ban the construction of minarets on mosques, according to results of a referendum held Sunday.

In this Oct. 26, 2009, file photo, pedestrians walk in Zurich below posters promoting a "Yes" to the initiative banning the construction of minarets in Switzerland. (Steffen Schmidt/Keystone/Associated Press)

Some 2.67 million people voted 57.5 to 42.5 per cent in favour of the initiative. Voters in only four of the 26 cantons, or states, opposed the proposal, paving the way for a constitutional amendment.

Polls conducted before the referendum showed that only 37 per cent of voters support the ban on new minarets.

The nationalist Swiss People's Party, the largest party in parliament, had pushed for the national vote after labelling the mosque towers as symbols of militant Islam.

Walter Wobmann, president of a committee that backed the initiative, said its aim is not to stop people from practising their religion, but to stop political Islam and the "further Islamization of Switzerland."

Supporters of the ban claim that allowing minarets would represent the growth of an ideology and the Islamic legal system Shariah, which they claim are incompatible with Swiss democracy.

Amnesty International, though, has warned that such a ban would violate Switzerland's commitment to religious freedom.

Swiss Muslims say the recent construction of Sikh temples and Serbian Orthodox churches is proof that Islam is being singled out for discrimination.

"The initiators have achieved something everyone wanted to prevent, and that is to influence and change the relations to Muslims and their social integration in a negative way," said Taner Hatipoglu, president of the Federation of Islamic Organizations in Zurich.

The seven-member Swiss cabinet also spoke out against the initiative, put to a referendum after members of the Swiss People's Party and the Federal Democratic Union collected 100,000 signatures from eligible voters who said they were in favour of a nationwide vote.

The Swiss government argued a construction ban would cause "incomprehension overseas and harm Switzerland's image" and it reminded voters that Swiss mosques currently do not broadcast the call to prayer outside their buildings.

In the country of 7.5 million people, about 400,000 are Muslims, most of them immigrants from Turkey or the Balkans. Fewer than 13 per cent actively practise their religion, the Swiss government says.

Only four of the country's estimated 150 mosques have a minaret, while a fifth tower has recently been approved for construction.