Protesters have been on the streets in the Georgian capital since April 9 demanding the resignation of President Mikheil Saakashvili.
Wooden jail cells, which the opposition says symbolize the country's descent into a police state, have already been built on Tbilisi's central street.
The Georgia Online news website reported on Monday that the Georgian authorities had set the protesters a deadline of May 16 to clear the main street, warning that otherwise the police would have to resort to force.
The authorities said such a measure was connected with the forthcoming May 26 Independence Day celebrations, when the central street is traditionally used for military parades.
Saakashvili, a U.S.-educated lawyer who came to power on the back of 2003 street protests, has been criticized for his authoritarian leadership and for dragging the country into a disastrous war with Russia last August, which resulted in the permanent loss of two separatist provinces.
Tens of thousands of opposition supporters gathered in the capital, Tbilisi, on the first day of the protests. Several thousand protesters remain gathered in the city center, with activists picketing the presidential residence day and night.
