The initiative puts a 20 percent cap on the proportion of holiday homes in mountain villages and bans further construction in municipalities where this level is already reached or exceeded.
The Helvetia Nostra group which spearheaded the initiative has raised concerns about a lax interpretation of the initiative, with loopholes that would allow secondary residences to continue to proliferate, threatening the environment of Swiss mountain areas.
But earlier this week, Vera Weber, Helvetia Nostra president, reached a deal with the right-wing Liberals and Swiss People’s Party for a law to “put an end to the invasive construction of secondary residences”.
Under the agreement, new holiday homes would not be permitted if they are subsequently advertised for rent on the internet.
Weber also got the parties to agree to limit the amount of space in hotels that could be converted to holiday flats to 50 percent.
And the deal also scraps the possibility of transforming a structure worthy of protection — such as a matzot (mountain hut) — into a secondary residence.
A spokesman for the Swiss People’s Party said they agreed to the deal because it was important to respect the will of the people and also to put an end to the uncertainty about the implementation of the initiative.
Not everyone is happy with the agreement, however, particularly certain politicians from cantons such as Valais, where the restrictions are seen as a drag on economic development in mountain areas that are already struggling to deal with the strong franc.