The drastic immigration reduction in Switzerland will isolate the country and will damage its ties with the European Union, left-wing groups said on Monday, urging voters to reject the proposal.

On November 30, Swiss voters will decide in a referendum whether the country should cap immigration to 0.2% of the population or 16,000 people a year.

In 2013, net migration was five times higher - 82.8 thousand people, according to the national statistics.

The initiative "Stop overpopulation - safeguard our natural resources" was launched by the environmentalist group Ecopop shortly after voters narrowly backed the proposal to introduce quotas on EU citizens. This has triggered strong criticism from Brussels, Reuters notes.

Opponents of Ecopop's idea claimed that the proposal would be detrimental to the bilateral relations between Switzerland and Brussels which govern commercial, agricultural, economic and technological cooperation.

The Swiss government is still deciding how to implement February's votes. The bill from June to reintroduce quotas on EU citizens from 2017 was sharply criticized by Brussels.

According to Regula Rytz, co-president of the Green Party, the rejection of the Ecopop initiative would be the first and most important step against Switzerland's political isolation.

Ecopop says that the lack of living space exerts too much pressure on the natural resources in landlocked Switzerland, which has a population of over 8 million people.