Swiss voters have backed the government's plan to provide billions of dollars in subsidies for renewable energy, ban new nuclear plants and help bail out struggling utilities in a binding referendum.
Provisional final figures on Sunday showed support at 58.2 per cent under the Swiss system of direct democracy, which gives voters final say on major policy issues.
The Swiss initiative mirrors efforts elsewhere in Europe to reduce dependence on nuclear power, partly sparked by Japan's Fukushima disaster in 2011. Germany aims to phase out nuclear power by 2022, while Austria banned it decades ago.
"The results shows the population wants a new energy policy and does not want any new nuclear plants," Energy Minister Doris Leuthard said, adding the law would boost domestic renewable energy, cut fossil fuel use and reduce reliance on foreign supplies.
Debate on the "Energy Strategy 2050" law had focused on what customers and taxpayers will pay for the measures and whether a four-fold rise in solar and wind power by 2035, as envisaged in the law, can deliver reliable supplies.
Leuthard has said the package would cost the average family 40 francs more a year, based on a higher grid surcharge to fund renewable subsidies.
Critics said a family of four would pay 3200 Swiss francs ($A4410) in extra annual costs, while more intermittent wind and solar energy would mean a greater reliance on imported electricity. Switzerland was a net power importer in 2016.
The electrical and mechanical engineering sector, which opposed the law, said it was important to see how it is implemented.
Solar and wind now account for less than five per cent of Switzerland's energy output, compared with 60 per cent for hydro and 35 per cent for nuclear.
The law will ban building new nuclear plants. Switzerland has five plants, with the first slated to close in 2019. Voters have not set a firm deadline for the rest, allowing them to run as long as they meet safety standards.
