The New Democracy MEP, Manolis Qefalojanis, spoke after visiting the prison in Albania, where he met the citizen Fredi Beleri.
Qefalojanis has not hesitated to put pressure on Albania to join the European Union.
"Fredi Beleri continues his proud fight for the Greek ethnic minority, for the residents of Himara. He has been imprisoned for a year now, on a flimsy and baseless charge, an unjust decision that keeps him in prison illegally," he said.
Kefalogiannis also warned that jailing Beler, who New Democracy ran for European Parliament elections in June, would hinder Albania's chance to join the bloc.
"Albania's membership course depends on the respect of the fundamental rights of the Greek ethnic minority, on the solution of the ownership issue in Northern Epirus, on the respect of good neighborly relations, on the immediate release of Fredi Beleri and on his oath as the Mayor of Himara", he said.