The Panepistimio metro station in central Athens closed at 11 a.m. on Thursday by order of the police, due to a rally planned to protest against legislation reforming tertiary education.
The rally will start at 1 p.m. at the University of Athens central building.
Trains will continue to pass through the station without stopping.
The protest is a reaction to the University reform bill presented by Minister for Education Niki Kerameus in January.
The controversial aspect of the bill includes measures to tackle lawlessness in Greek universities, including the creation of a new campus police force.
Critics say the bill will stifle freedom of expression for students, but the government maintains it will improve the quality of higher education.