Slovakia filed a lawsuit at the European Court of Justice on Wednesday against a European Union decision to redistribute 120,000 asylum seekers among member countries, the first legal challenge to a measure that has divided the bloc.
So far this year, nearly 890,000 migrants and refugees have reached European shores, about four times the total in 2014, according to U.N. data. The question of how to cope with the mass inflows have caused a rift between EU governments.
Germany and France threw their weight behind a quota system to help redistribute migrants across EU members, but some of the smaller, less wealthy and more socially conservative countries in the bloc strongly rejected the idea.
Slovakia, the Czech Republic, Hungary and Romania opposed mandatory quotas, but were outvoted at a meeting of EU interior ministers in September.
"We demand that the court rules the decision on imposing mandatory quotas is invalid," Fico told reporters.
"I consider the quotas to be nonsensical and technically impossible. Our words are being proven true, the quotas have become a fiasco."
Slovakia, which is due take in 802 migrants under the scheme, argues it has no power to keep migrants in if they wish to move on to Germany and other richer EU member states. Slovakia has only received 154 asylum requests this year.
Hungary is also planning to challenge the quotas. Prime Minister Viktor Orban said on Wednesday that EU and Turkey could announce an agreement within days to resettle 400,000 to 500,000 Syrian refugees directly from Turkey to the EU.
Orban said he expected intense pressure from Europe to accept some of these refugees, something he said Budapest could not do.
The Czechs and Romanians have said they will not sue.
Poland's new government has overturned previous centre-right pro-EU cabinet's pledge to take in thousands of refugees, saying the attacks on Paris showed the need to review the quota system.