The Georgian police on September 6 arrested 29 activists of a number of several opposition groups aligned with the Justice Party of Igor Giorgadze.
Tbilisi's chief prosecutor said one suspect will also be charged with illegal possession of arms. A number of detainees have been released.
Among those detained were several key opposition figures.
Georgian President Mikheil Saakashvili says anyone convicted of plotting to overthrow the government will "get what they deserve." Speaking during a visit to Poland on September 6, Saakashvili suggested the alleged coup plotters were financed from abroad.
Commenting on the arrests, the speaker of Russia's State Duma, Boris Gryzlov, today said an "authoritarian regime" has been established in Georgia.
Giorgadze, a former minister for national security who is now believed to be living in Russia, is wanted in Georgia on charges of attempting to assassinate former President Eduard Shevardnadze in 1995. He has repeatedly called for Saakashvili's resignation.
(civil.ge, Interfax, Rustavi-2, RIA Novosti)