Opposition politicians estimate that up to 100,000 people will take part in the rally in the Georgian capital. The rally is to begin at 4.00 p.m. (noon GMT) on Friday and last until February 25.
The country's Labor Party and Christian Democratic Movement said they would attend the protests, while a number of Georgian opposition parties, including the New Right party, have not yet confirmed their participation.
On January 13, Georgia's central election commission officially announced Saakashvili as the winner of an early presidential poll in the South Caucasus republic with 53.47% of the vote. His nearest rival, united opposition candidate Levan Gachechiladze, won 25.69%.
However, the Georgian opposition said the election results were rigged and demanded a second round in the January 5 presidential elections. On January 13, when the official election figures were announced, the Georgian opposition held a rally in Tbilisi to protest the vote results.
Saakashvili called the snap elections following mass street protests in Tbilisi in early November fueled by popular discontent with his alleged totalitarian tendencies and the country's economic woes. He ordered a brutal police crackdown on protesters and briefly imposed state of emergency, triggering criticism from his Western allies.
Three rallies were held by Georgia's opposition in Tbilisi on Tuesday, including a march by youth opposition movements against the detention of activists during last year's protests against President Mikheil Saakashvili.
