On Wednesday, the protesters gathered on central Habib Bourguiba Avenue in the capital, waving Tunisian flags and shouting slogans such as: "The people want the fall of the regime", "Get out" and "Government of traitors, resign!"
The demonstration took place amid a heavy security presence, with armored vehicles and anti-riot police deployed along the central Tunis boulevard, which was the epicenter of the January 2011 revolution that ousted former President Zine El Abidine Ben Ali.
A rival rally planned by the League for the Protection of the Revolution, a controversial pro-government armed group, failed to materialize.
Wednesday's demonstration came just hours before the start of a planned national dialogue between the ruling party Ennahda and the opposition, which has now been delayed until Friday.
Mediators hope the talks will bring an end to the political paralysis gripping the country since the July killing of opposition MP Mohamed Brahmi and mark a crucial step in the country's democratic transition.
"We hope that Larayedh will have enough courage to announce the resignation of his government within three weeks to save the country," Hamma Hammami, a leader of the opposition Popular Front party.
The Tunisian Prime Minister Ali Larayedh on Wednesday confirmed Ennahda was ready to resign, but insisted on the completion of the country's new constitution, the establishment of an electoral commission and a clear election date before handing over power.
Meanwhile, seven Tunisian police were killed and one injured in clashes with gunmen in the central Sidi Bouzidi province, as the country waited for the government's expected resignation and the launch of talks on ending months of political deadlock.
Fighting erupted in the central Sidi Bouzid region, when members of the National Guard raided a house where the gunmen were holed up, a police source said.
Moncef Marzouki, the Tunisian president, announced three days of national mourning.
"It is not a coincidence that they decided to attack the National Guard. Every time we reach a consensus terrorism rises again," the Tunisian president said.
NTJ/NJF