Religious leaders in Tunisia appealed for calm at Friday prayers in mosques across the country, with police out in force after a wave of rioting involving Islamic fundamentalists.

Several groups, including hardline Salafists, cancelled planned rallies after the government issued a ban in the wake of the worst unrest since the revolution that ousted longtime president Zine El Abidine Ben Ali in January last year.

"The security situation is normal throughout the country, there is no reason for citizens to be afraid," interior ministry spokesman Khaled Tarrouche told local radio.

One person was killed and more than 100 injured in the clashes, which also saw police stations and political offices torched, after Salafists took issue with art works at a Tunis exhibition they deemed offensive to Islam.

The authorities slapped a curfew on the capital and several other parts of the country and arrested over 160 people but there were fears that the calls for rallies Friday to promote "sacred values" could spark further clashes.

"We call on all citizens to go about their normal activities, there is no reason to be afraid," Tarrouche stressed, adding that the security forces "were ready to confront any kind of threat."

Police reinforcements were deployed along Bourguiba Avenue, a main thoroughfare in central Tunis which has been traditionally been used for mass demonstrations, but no incidents have been reported.

"We are all brothers, we are all Muslims," said Religious Affairs Minister Nouredine Khadmi, a former imam who gave a sermon at Al-Fath mosque, often the starting point for demonstrations by Salafists.

He called for unity among the people of Tunisia and warned against "sedition"

At the last minute on Thursday, the fundamentalist Ansar al-Sharia movement and Hizb Ettahrir, as well as the moderate Ennahda party which dominates the government, announced their planned rallies would not go ahead on Friday.

Hardline Islamists have been growing more confident since the popular revolt that toppled Ben Ali, the first of the Arab Spring uprisings that ousted several other autocratic leaders.

With the moderate Islamists of Ennahda gaining the upper hand in Tunisia, the Salafists have been pushing for sharia to be recognised as the main source of law in the currently secular country.

As well as the weekend attack on artwork deemed "blasphemous", Salafists have in recent months also staged attacks on bars or shops selling alcohol.

Al-Qaeda's chief Ayman al-Zawahiri had urged Tunisians in a weekend message to rise up to demand the rule of Islamic law, and lambasted Ennahda for "violating" sharia.

But Ennahda leader Rached Ghannouchi denied that Zawahiri's rallying cry had triggered the violence, saying he had no influence in Tunisia.

While the situation remained calm in the centre of Tunis on Friday, tensions were high with residents wary of another outbreak of violence.

"We are afraid. We don't know if the government is really controlling the situation," trader Hedi Barrouche told AFP.