Local residents said police clashed with several hundred young men in the centre of Ben Guerdane.
The youths tossed rocks and petrol bombs in the protests.
Six years after their revolt ousted autocrat Zine El Abidine Ben Ali, Tunisia’s central and southern regions are still flashpoints for rioting in marginalised towns where many young Tunisians see little economic progress since the uprising.
Local residents said police clashed with several hundred young men in the centre of Ben Guerdane and that protesters lobbed rocks and petrol bombs and set tyres ablaze.
“Police are firing tear gas to try to disperse hundreds of youths who are protesting in the centre of the town demanding work,’’ Fethi Chandoul, a local resident said.
Residents and local media said shops and offices were closed for a general strike in Ben Guerdane, the site of an Islamic State attack last year by militants’ crossing over from nearby Libya.
Around 4,000 protesters also marched peacefully in the central town of Meknessi to demand work opportunities and development projects.
Prime Minister Youssef Chahed was sending a ministerial delegation to Ben Guerdane on Friday to talk with protesters, according to the state news agency TAP.
Since the 2011 uprising, Tunisia has mostly avoided the political violence that has plagued much of the Arab world.
The North African country emerged as a model of peaceful democratic transition with free elections, a new constitution and compromise between Islamist and secular rivals.
But economic progress, a central demand of many Tunisians, has failed to match the country’s political advances.
In rural southern and central regions, where farming remains one of the few sources of income, tensions often flare over the dearth of jobs.