The opposition started the protests on April 9, vowing to hold them daily until Saahashvili steps down.
"I am prepared to cooperate with all the political forces, including the most radical of them," Saakashvili told workers at a factory near Tbilisi. "Georgia now needs our unity, not conflicts."
Saakashvili pledged to iron out political differences and create jobs in the ex-Soviet Caucasus state, which has been hard-hit by the global financial crisis.
Opposition groups have criticized Saakashvili, a U.S.-educated lawyer who came to power on the back of mass street protests five years ago, of failure to carry out democratic reforms and for dragging the country into the disastrous war with Russia last August, which resulted in the permanent loss of two separatist provinces.
Thousands of new supporters arrived in the capital, Tbilisi, from provinces late on Wednesday.
Opposition activists have built wooden jail cells on Tbilisi's central street to symbolize the country's descent into a police state. Protesters remain gathered at the State Chancellery and parliament building, the presidential residence, and state television headquarters. Police have not attempted to disperse the rallies.
