Tens of thousands of people took to the street last Thursday and on Friday blocked major roads running past the president's residence and the public broadcaster's headquarters as part of a campaign of civil disobedience.
"The campaign will last round-the-clock here," said Kakha Kukava, a Conservative Party member.
There will also be protests in front of the parliament every afternoon.
Activists are planning to put up improvised prison cells around Tbilisi to symbolize the country becoming a "police state."
"We will turn Tbilisi into a city of tents and cells," United Opposition leader Levan Gachechiladze said. Campaign leaders, politicians and ordinary people will take part.
The opposition will announce further plans at a meeting to be held near the parliament after 3:00 p.m. local time (11:00 GMT). However, an announcement has already been made to hold a tie campaign at the presidential residence at 5:00 p.m. (13:00 GMT).
Saakashvili was caught on camera in August nervously chewing his necktie while discussing the Georgian-Russian conflict by telephone with a top Western official.
A Conservative activist, Lasha Chkhartishvili, urged residents gathering in front of Saakashvili's residence to bring ties and hang them on the fence.
"It will be a sort of 'a tree of wishes.' Everyone who puts a tie on it can make a wish. And I am sure everyone will have the same wish - for the president to step down," Kukava said.
In Moscow, activists from the pro-Kremlin youth group Nashi (Ours) intend to bring over 1,500 wilting roses to the Georgian Embassy to symbolize the failure of the "Rose Revolution" that brought Saakashvili to power.
The Georgian president is facing the toughest challenge yet to his leadership amid public anger over last summer's disastrous war with Russia, which resulted in the independence of the breakaway republics of South Ossetia and Abkhazia, and criticism for failure to carry out democratic reforms promised after he came to power in 2003.
