The hard-right Swiss People's Party (SVP) slammed the verdict, calling the decision by the European Court of Human Rights "scandalous".

"Switzerland must withdraw from the Council of Europe," the SVP said in a statement.

The party comfortably topped the Swiss general elections in October but the seven government seats are shared between the four biggest parties -- which are often opposed to the government's collective decisions.

The Swiss Federal Office of Justice said only it had noted the verdict by the court in Strasbourg, France, and would consider the next steps.

"This ruling is final. This detailed judgement will be analysed with the authorities concerned and the measures that Switzerland must take for the future will be examined," it said in a statement sent to AFP.

The ECHR found that the Swiss state had violated Article 8 of the European Convention on Human Rights, which guarantees the "right to respect for private and family life".

The case was brought by the Swiss association of Elders for Climate Protection -- 2,500 women aged 73 on average.

"The Strasbourg judges have turned themselves into puppets of activists and have now finally lost their credibility. Your brazen interference in Swiss politics is unacceptable for a sovereign country," the SVP said.

They "did not even consider the fact that Switzerland is exemplary in reducing carbon dioxide emissions", it said.

The SVP said the ECHR was "increasingly interfering in national affairs" and it was "unacceptable that political decisions are made by courts".

The party, with its agrarian roots, takes a firm stand on upholding Swiss independence and opposing closer European integration.

Switzerland has a direct democracy system but the SVP did not say whether it intended to try to collect the 100,000 signatures necessary to trigger a public vote on leaving the Council of Europe.

- 'Historic victory' -

Left-wing and environmentalist bodies welcomed the ruling however.

Greenpeace Switzerland said the decision set a precedent for the Council of Europe's 46 member states.

"All these countries can now be asked by their citizens to examine their climate policy in order to guarantee respect for human rights, based on this case law," it said.

Alongside the Elders for Climate Protection, Greenpeace will now seek to take the matter to the International Court of Justice in The Hague.

The ruling was a "slap in the face" for the government and its "climate inaction", said Mattea Meyer, co-president of the Social Democrats, Switzerland's second-biggest party.

The party said that "only massive public investments will be able to ensure the energy and climate transition".

And the smaller Greens Party declared a "historic victory" and demanded the setting of new climate targets for the agriculture, finance and aviation sectors.

For domestic climate policy, "this decision is of comparable importance to the Paris climate agreement", said the party's new president Lisa Mazzone.

Meanwhile four activists sprayed a Swiss Porsche sales centre near Lausanne with orange paint, launching a campaign to "Liberate Switzerland" from cars, following the ECHR ruling.