Hungary's parliament on Tuesday voted in favour of a government proposal to hold a referendum challenging EU refugee redistribution quotas.
Conservative Prime Minister Viktor Orban's Fidesz party and the rightist Jobbik party supported the proposal, while the opposition was expected to file a constitutional challenge to the motion.
Hungary's Supreme Court gave Orban the green light last week to hold a referendum asking citizens if the European Union should be permitted to "impose the mandatory settlement of non-Hungarian citizens in Hungary without the consent of parliament."
The EU has been trying to implement a contentious scheme for the redistribution of 160,000 asylum seekers from overwhelmed member states such as Greece and Italy to other EU countries, but relocations have barely started amid opposition from Hungary and other Eastern European members of the bloc.
Under Hungarian law, a referendum is valid only on turnout of more than 50 per cent. The opposition already said it will seek to topple it with a boycott.
Orban's hostility to foreigners during the European migration crisis made international headlines when he commissioned the construction of a razor-wire-topped fence along Hungary's borders with Serbia and Croatia to block migrant arrivals.
He was particularly outspoken against Muslim refugees, saying they were unacceptable in mostly Christian Hungary.
Hungary opposed the EU refugee quotas scheme from the start and promised to legally challenge it at the European Court of Justice.