"Patarkatsishvili has been recognized as a suspect in participating in a conspiracy against the state, aimed at overthrowing power by forceful means," Nikoloz Gvaramiya said in a TV broadcast.
Georgian state television reported that prosecutors intend to put the businessman, currently in London, on an international wanted list.
Gvaramiya also said criminal proceedings have been launched against Patarkatsishvili, who founded the Imedi independent TV company. The station's broadcasts have been halted by authorities as part of emergency measures imposed by President Mikheil Saakashvili following six days of mass anti-president protests in Tbilisi.
The main state TV channel said investigators were considering Patarkatsishvili's statements at a November 2 rally, as well as a statement distributed by his press service saying he would give all his money to overthrow the leadership.
The tycoon also told Russia's Ekho Moskvy radio station: "I will do my best to free Georgia from this fascist. Until yesterday I believed the government would not dare fight against its nation, but yesterday's developments drastically changed my opinion."
A Georgian opposition leader, David Zurabishvili, ruled out on Friday that the opposition would nominate Patarkatsishvili for president at early elections set for January.
On Wednesday, riot police with shields and batons broke up mass rallies in central Tbilsi, injuring hundreds of protesters. The opposition supporters were demanding President Saakashvili's resignation and early parliamentary elections.
The following day, President Saakashvili said early presidential elections would be held on January 5, 2008. "I am cutting short my presidential term of my own will for a second time, and I am doing it in the full belief that Georgia is a democratic country. I think the people will demonstrate their will on January 5," he said.
He also said a plebiscite on parliamentary elections should be held alongside the presidential elections. Simultaneous parliamentary and presidential elections had previously been scheduled for the fall of 2008.
Georgia's last presidential elections were held on January 4, 2004, with a presidential term of five years.