(GENEVA) - Switzerland on Friday set out plans for new immigration quotas, four months after voters narrowly approved curbs and set the country on a collision course with Brussels.

The Swiss government, or Federal Council, said limits would come into force in February 2017.

That deadline was set in a referendum in February which was lauded by eurosceptics at home and abroad.

It added that to meet the needs of the labour market, it would tap "the potential of the workforce already available in Switzerland."

It also said that draft legislation would follow at the end of the year, and that quotas would not be ironclad.

"The Federal Council has refrained from setting a fixed, inflexible target for reducing immigration. A target of this type would make it impossible to respond to the changing economic and jobs situation when regulating immigration," it said.

Switzerland is not in the 28-nation European Union, but has a series of decade-old treaties governing ties with the bloc, its top economic partner.

They include a deal giving EU citizens free access to wealthy Switzerland's labour market.

Critics say that caused breakneck immigration and unfair competition for locals, offsetting the gains of Swiss companies' equal footing in the EU economy.

Under Switzerland's system of direct democracy, however, the people have the final say on a huge array of issues.

The February 9 referendum saw a hair's-breadth majority approve measures pushed by the right-wing populist Swiss People's Party, the largest single force in parliament.

It called for a reintroduction of work and residence permit quotas which applied to EU citizens in the past and remained in force for people from other nations.

It also demanded controls the tens of thousands of cross-border commuter whom head every day between homes in France, Germany and Italy and jobs in Switzerland.

- EU 'no intention' to allow quotas -

The rest of the Swiss political establishment and the business sector warned that reviving restrictions would hurt the economy.

Switzerland, a nation of eight million people, has long relied on migrant workers and, with some of the toughest citizenship laws in Europe, foreigners make up around a quarter of its population.

Brussels insists that the existing treaties with Switzerland are a package and that the country cannot pick and choose.

Free movement of workers is also a key tenet of the EU's own internal rules, but is under attack notably in western countries, with claims that migrants from ex-communist member states are hitting local workers.

Having pledged to defend the rules inside the bloc, Brussels is almost certain not to give the Swiss any leeway.

EU foreign policy spokeswoman Maja Kocijancic confirmed its concerns on Friday.

"Quotas and discrimination in favour of Swiss residents on the Swiss job market, are irreconcilable with the EU-Swiss agreement on the free movement of persons," she said.

She said the EU would examine Switzerland's draft law before giving an official answer.

But she underlined that the European Commission -- the bloc's executive body -- had "no intention" of giving a green light to quotas and national preference rules.

"Quantitative limits and national preference are contrary to our Treaties. Negotiating them is not an option for the Commission," she said.

The Swiss government played down the spectre of confrontation.

"The Federal Council plans to maintain and develop Switzerland's close and crucial relations with the EU and its member states," it said.

The government could end up having to call a fresh referendum to ask voters if they are ready to rip up the entire set of treaties in return for immigration controls.