"Those who have been arrested number 200," Larayedh said at the Doha Forum in the Gulf state of Qatar, quoted by the Arabic daily Al-Hayat.
The Tunisian leader warned of firm action against Ansar al- Sharia, an organisation that he said has links to and is involved in "terrorism".
"This group is engaged in violence, is opposed to the state and revolts" against the authorities, he said, according to Al-Hayat.
One protester was killed and 15 policemen wounded in the clashes that broke out in Tunis yesterday after the authorities banned Ansar al-Sharia from staging their annual congress.