Starting 1 May, the nationals of the so-called EU-8 (the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia and Slovenia) will have to seek authorisation to work in Switzerland, the government said in a statement.
"In a recession, immigration from the EU has had a positive impact on consumption and investment in building, thus strengthening, the Swiss economy. More than 1.1 million citizens of EU member countries live in Switzerland. They play an important role, as well as the border, the Swiss economy and the creation or retention of jobs in Switzerland," the statement reads.
The statement also says there is need for a debate on labour market measures, including measures to facilitate migrants' integration.
Swiss authorities have also been requested to formulate proposals to address non-compliance by subcontractors of requirements on the minimum wage, working conditions and taxation.
Ashton said she regretted the decision of the Swiss authorities.
"I consider this measure to be in breach of the Agreement on the Free Movement of Persons as amended by the Protocol of 2004. The agreement does not allow for any differentiation between EU citizens. This measure is neither economically justified by the labour market situation nor by the number of EU citizens seeking residence in Switzerland," Ashton said in a statement.
Switzerland opened its labour market to the EU-8 on 1 May 2011. However, the country has decided to make use of a "safeguard clause" in its freedom of movement agreement with the EU.
The clause allows it to unilaterally re-introduce quotas for nationals from the countries if the number of residence permits exceeds by more than 10% the average number issued in the three previous years.
As a result, a quota of 2,000 B-type long-term permits (for one year or more) will enter into force on 1 May for one year. Before the expiry of this period, the Swiss authorities would examine the situation and decide whether to extend the restriction until 31 May 2014. No restrictions for EU-8 nationals are possible after this date.