TUNIS - Tunisia's government on Wednesday sought to contain some of the worst unrest since last year's democratic revolution after rioting blamed on hardline Islamists led to 165 arrests and a nighttime curfew.

One man died and around 100 people were injured, including 65 policemen, as a result of the wave of unrest, which appears to have been triggered by an art exhibit that included works deemed offensive to Islam.

A 22-year-old protestor who sustained a bullet wound to the head during clashes between Salafist protestors and police Tuesday in the eastern city of Sousse died of his wounds in hospital, an official said.

On the last day of the exhibit entitled "The Spring of the Arts" in the northern Tunis neighbourhood of La Marsa Sunday, two individuals requested that "blasphemous" works be pulled down.

Secular activists and artistic circles soon rallied their troops over social networks for a showdown at the venue aimed at defending freedom of expression and the right to artistic creation.

Later on Sunday, several men identified as Salafists entered the art gallery and destroyed several pieces on display.

The ultra-conservative Islamists denied involvement but the incident sparked clashes Monday and Tuesday that saw police stations, political party offices and a court torched in Tunis and several other parts of the country.

Justice Minister Nourredine Bhiri condemned the violence and pledged that the guilty would pay a heavy price. "These are terrorist groups which have lost control, they are isolated in society," he told radio Shems FM.

The authorities on Tuesday imposed a dusk-to-dawn curfew in eight of the North African country's regions, including the greater Tunis area.

Tension remained high on Wednesday as artists were scheduled to hold a rally in front of the ministry of culture.

Some Tunisians accuse the government, led by Islamist party Ennahda, of being too lenient with the Salafists, who have aggressively pushed their agenda since the January 2011 fall of president Zine el Abidine Ben Ali.

A radical imam, Abou Ayoub, said in a video circulated on Facebook: "The Muslim population must rise up Friday after prayers in response to those who mock Islam."

"Since the fall of Ben Ali, the infidels have not stopped mocking our religion, and it's becoming more frequent every day," said Ayoub, who had called in October 2011 for attacks on television station Nessma after it broadcast the French-Iranian animated film "Persepolis".

Commentators said the overnight unrest started just two days after Al-Qaeda chief Ayman al-Zawahiri called on Tunisians to demand the imposition of Sharia, or Muslim religious law.

Others suspected a plot by Ben Ali sympathisers to destabilise the country and reclaim power.

"The fact that the violence erupted in several places at the same time makes us think that it was organised," said Tarrouche.

A military court on Wednesday sentenced Ben Ali to 20 years imprisonment in absentia on charges of "inciting disorder, murder and looting" over the deaths of four youths, killed in the town of Ouardanine in mid-January 2011.

Four protestors were shot dead in the eastern coastal town as they tried to prevent the flight of Ben Ali's nephew Kais, a day after the strongman himself flew out of the country on January 14.

The victims' relatives have accused the security apparatus of ordering police to open fire on the crowd.

Ben Ali, who lives in exile in Saudi Arabia, faces countless trials and has already been sentenced to more than 66 years in prison on a range of other charges including drug trafficking and embezzlement.