During the meeting, the composer lodged an official objection to the Memorandum signed by Greece for the EU financial aid package, questioning whether this was compatible with the country's Constitution.
Theodorakis, who launched an independent citizens' movement called 'Spitha' in 2010 after the Greek debt crisis emerged, was accompanied by constitutional law expert George Kasimatis.
"The Memorandum and loan agreements are constitutionally invalid, since they were not signed by three fifths of Parliament, nor by the President of the Republic but only by the Finance Minister George Papaconstantinou," Theodorakis said in a statement as he emerged from the meeting.
"With [Prime Minister George Papandreou's] unacceptable surrender we conceded a part of our national sovereignty. We had said that if the Memorandum was implemented our country would be led into chaos. We have reached the point of no return. There is no other solution. This is why the government is seeking support in consensus and Europe is almost extortionately saying that there must be national unity. But how can this happen when the two largest parties cannot even claim 40 percent [of the vote]," he added.
According to Kasimatis, Greece was a "country under occupation" and the only solution was for people to take matters into their own hands. He asserted that the terms contained in the Memorandum violated all the fundamental principles of the Constitution, European legality and international law.