Tensions have frayed across Tunisia, particularly in Sidi Bouzid, cradle of the 2011 Arab Spring uprising that toppled Ben Ali, and home town of an opposition MP who was assassinated on Thursday.

Mohamed Brahmi was the second opposition politician killed after Chokri Belaid was gunned down outside his home in February and many Tunisian blame the government for both killings.

Government detractors say the Ennahda-led cabinet has failed to rein in radical Islamists who have grown in influence and stand accused of a wave of attacks since the 2011 uprising.

The government talks had been due to start at 0800 GMT but ministers were late arriving and the meeting had yet to get under way at 1100 GMT, an AFP correspondent reported.

A meeting of the 500,000-member strong General Union of Tunisian Labour (UGTT) that was due to convene in the afternoon "to decide the fate" of the country, was also delayed, its secretary general Sami Tahri said.

Ahead of the two meetings, anti-government protests erupted in both Tunis and Sidi Bouzid, with demonstrators demanding the resignation of the government and the dissolution of parliament.

In both cities, police used tear gas to disperse the protesters.

In the center-west city of Sidi Bouzid, they fired tear gas to disperse stone-throwers among a crowd of hundreds of protesters who blocked employees from going to work at the governor's office.

The demonstrators also demanded the dismissal of the governor of Sidi Bouzid, who is regarded as close to the Islamists.

In Tunis, police fired tear gas to disperse a group of diehard protesters who rallied outside the National Constituent Assembly for a fourth day running.

Overnight around 10,000 people demonstrated for and against the government on Bardo Square outside the parliament building, separated by police vans and metal barricades.

Protesters, including opposition MPs and secular politicians, say parliament must be dissolved and a government of national unity formed.

NJF/NJF