Former Tunisian Interior Minister Rafiq Belhaj Kacem was arrested on Sunday, Doha-based al-Jazerra TV reported.
Kacem, who has been sacked by deposed Zine El Abidine Ben Ali in early December in an attempt to quell the protests, was captured in his hometown of Beja, about 110 km west of the capital Tunis.
The head of presidential guard and 50 others were arrested by the army, which were heavily deployed in the streets to restore order to Tunisia after the breakout of violence and social unrest and the toppling of Ben Ali.
The official news agency TAP said head of presidential guard Ali Seriati and a number of his colleagues have been arrested over accusations of fomenting the recent wave of violence and unrest in Tunisia.
"An investigation has been launched against the head of the presidential guard and a group of his accomplices for plotting against the security of the state," the agency said.
It said they were also accused of instigating a string of killing, unrest and looting sprees in "the Tunisian soil and therefore a judge issued arrest warrants against them."