Media reports counted several dozen protesters who hunkered down behind barbed wire and barricades at the Mogamma building in Tahrir Square, one of the largest government administration facilities in Egypt.
The protesters called for the current Muslim Brotherhood government led by President Mohamed Morsi step aside and order early elections. They also demanded the new Egyptian constitution be replaced.
Ahram Online said the blockade irked a number of Egyptians trying to enter in order to attend to personal business but the scene was otherwise quiet.
The protest was seen as being part of a larger campaign of civil disobedience in the run-up to the anniversary of President Hosni Mubarak's ouster, the Egypt Independent said.