Hungary anti-Semitism: MP condemned over 'list of Jews'
MP Marton Gyongyosi, deputy group leader of Jobbik, spoke during a parliamentary session on Monday.
The government responded by saying it condemned "to the greatest possible degree" Mr Gyongyosi's statement.
Jobbik has 47 seats in the 386-seat parliament - the third-largest group.
Jobbik, an opposition party purporting to protect Hungarian values and interests, also has three MEPs in the European Parliament. The party has been linked to uniformed vigilantes who say they are safeguarding public order in areas with large Roma (Gypsy) communities.
During a debate on the conflict in the Gaza Strip, Mr Gyongyosi said it was time to "assess how many MPs and government members are of Jewish origin and who presents a national security risk to Hungary".
The statement from a government spokesman on Tuesday said the government took "the strictest possible action against every form of racism and anti-Semitic behaviour" and did "everything in order to ensure that malicious voices incompatible with European norms are driven back".
"The government also makes it clear that every citizen will be protected from such insults," the spokesman added.