Defence lawyer Ayachi Hammami said the 13 were among 49 judges reinstated in August.
But the justice ministry has been investigating his 13 clients for "terrorist crimes mentioned in security reports," he added.
"This case is purely political," Hammami said.
The accused judges are to appear before the Supreme Judicial Council (CSM) on January 24, he told AFP.
The move comes nearly seven months after President Kais Saied sacked 57 judges, accusing them of corruption and blocking enquiries into two left-wing political figures in 2013, among other purported transgressions.
Saied staged a dramatic power grab in July 2021, sacking the government, suspending parliament and rocking the foundations of the only democracy to have emerged from the Arab Spring uprisings.
In February he dissolved a previous top judicial body, replacing it with the CSM whose members the president picks -- and can sack without appeal.
Rights groups Human Rights Watch and Amnesty International had slammed the suspensions as "a direct attack on the rule of law", and Tunisian lawyers went on strike for a month in response.