Hungary's parliament could change the constitution to reject the EU's mandatory migrant resettlement on November 8, with the ban taking force by mid-November, the ruling Fidesz party said on Tuesday, after a weekend referendum vote against the quotas.
Lajos Kosa also told a news conference that Hungary's ruling party was committed to the country's European Union membership.
Speaking at the same news conference, Prime Minister Viktor Orban said: "We have to state clearly that without the approval of Hungarian parliament, Brussels ... cannot settle any migrants in Hungary. And we have to state clearly that we ban the forced resettlement of migrants."
An overwhelming majority of Hungarians rejected the EU quotas at a referendum on Sunday even though turnout was too low to make the vote valid.
That deprived Orban of a clear-cut victory and the radical nationalist Jobbik party on Monday called on him to quit.
But Orban said even though the referendum was not legally binding, it gave him a strong political mandate to challenge Brussels as more than 3 million voters rejected the quotas.
Orban has been one of the most vocal opponents to immigration within the EU. Last year Hungary was the main entry point into the EU's border-free Schengen zone for migrants traveling by land until Orban shut the Croatian and Serbian frontier by putting up a razor-wire fence.
Hungary is already fighting an EU relocation scheme established during the height of the crisis last year, which set quotas for each EU country to host a share of the migrants for two years. Along with Slovakia, Budapest has launched a court challenge against that plan.
Orban said on Tuesday that the referendum and the planned new law would not be able to prevent the relocation of about 1,300 migrants under last year's EU scheme if Hungary loses that court case.
But he said the new law would prevent any further EU migrant quotas being enforced in Hungary.
"What we can do is that we do not let EU decisions made after the referendum and the constitutional amendment take effect in Hungary," he said.