ZURICH (Reuters) - Swiss voters on Sunday approved making it easier for third-generation immigrants to become citizens, dismissing suggestions that the move could pose a security threat.

Projections by broadcaster SRF after polls closed showed the measure easily winning by a 59-41 percent margin.

Right-wing activists had used posters showing a burqa-clad woman with the slogan “no unchecked naturalization” to campaign against the proposal, which was backed by the government and parliament.

Around a quarter of neutral Switzerland’s population is foreign, a relatively high rate in comparison with other countries that make it easier for the children and grandchildren of immigrants to be naturalized.

The government had lobbied for the measure helping many young foreigners born and raised in Switzerland after their grandparents moved here. Under the current system they had faced a lengthy and often expensive naturalization procedure.

The new constitutional amendment simplifies -- but does not make automatic -- naturalization for well-integrated people no older than 25 who were born in Switzerland, went to school here for at least five years, share Swiss cultural values, speak a national language and do not depend on state aid.