A fresh demonstration in protest at the name deal between Greece and the Former Yugoslav Republic of Macedonia (FYROM) is scheduled to take place on Friday, to coincide with a vote in Parliament on the controversial agreement.
The vote has been scheduled for 2.30 p.m. but could run on later as MPs have their say, and protesters will likely begin gathering at Athens's main square after 12 noon.
The rally, which will be the third in less than a week held to express opposition with the agreement, is expected to affect traffic and public transport in the city center.
Police last Sunday and on Thursday closed down the Syntagma metro station as well as key streets around Parliament as part of security measures.
Both rallies were also marred by clashes between far-right extremists and police.
Protest rallies are also being held in Thessaloniki and other Greek cities against the deal.