Earlier this year, citing national security concerns, his government announced a so-called "Stop Soros" package of laws aimed at tightening rules for NGOs receiving funding from overseas.
The prime minister views Soros as an intruder into the country's domestic politics, which are more and more being painted by Europe's growing 2015 migrant crisis.
The legislation is branded as "Stop Soros" and the Hungarian government warned on Monday that legislative measures may yet become tighter. The move represents another example of the battle between Prime Minister Viktor Orban and non-governmental organizations (NGOs).
Worldwide charity Funds "open Society", founded by financier and philanthropist George Soros, covers the global activities in Budapest.
Patrick Gaspard, president of the Open Society Foundations, said on Tuesday that Budapest had "denigrated and misrepresented" the organization's work and repressed civil society "for the sake of political gain".
Soros' Open Society Foundations, which promote democracy and free speech, have also endured threats of legal sanctions from the government.
The foundations have been a frequent target of the Hungarian government, and Orban himself has painted Soros as a shadowy figure seeking to undermine the country's sovereignty.
The theme of thwarting Soros's alleged efforts to encourage immigration dominated the election campaign during which Orban said some 2,000 "mercenaries" paid by Soros were working in Hungary.
Some Hungarian Jews, in addition to Soros himself, find the campaign anti-Semitic.
According to reports, George Soros' Open Society Foundations will close their office in the Hungarian capital and move to Berlin.
OSF cited the safety of its more than 100 employees in Hungary as well as the security of its operations there, which fund dozens of NGOs in the country of 10 million.