After being brought before a magistrate in the northern city of Subotica, the police escorted Torockai to the border with Hungary and banned him from entering Serbia and Montenegro for a year.
The 64 Counties Youth Movement calls for revision of the Hungarian borders and the Trianon Treaty, under which Hungary lost several regions, including Vojvodina, as a result of which a third of all Hungarians became a minority in neighbouring countries.
"I consider it a gross violation of human rights and I will therefore turn to international forums, such as the court in Strasbourg and members of the Vojvodina, Hungarian and European parliaments," Torockai said in a written statement.
Torockai said his expulsion was connected with last week's celebration of the 1956 Hungarian Revolution in the village of Mali Idjos, which is predominantly populated by ethnic Hungarians.
The event, organised by the 64 Counties Youth Movement, was portrayed in the Serbian media as "a fascist feast of young Hungarians" because of the iconography used and statements made by some politicians from Hungary.
The Hungarian Foreign Ministry on Thursday joined Serbian politicians and state officials in condemning the behaviour of people who had attended the gathering.
Hungarian Foreign Ministry spokesman Viktor Polgar said that the Serbian authorities had probably expelled Torockai with an appropriate explanation.