The arrests of former justice minister Noureddine Bhiri and Mosaique FM director Noureddine Boutar on Monday night were the latest in a crackdown that has targeted activists, former lawyers and a prominent businessman.
Dozens of police officers raided Bhiri's house in Tunis and "took him to an unknown location", Ennahdha spokesman Abdelfattah Taghouti told AFP.
Bhiri, 64, had been detained for more than eight weeks early last year, a few months after President Kais Saied froze the Ennahdha-dominated parliament in a power grab his opponents have described as a coup.
During his detention, Bhiri staged a hunger strike, stopped taking medicines and was hospitalized before agreeing to be fed by drip.
He was later released but remains under investigation on charges related to "terrorism", according to authorities.
Mosaique FM, a popular news station, reported that police had also detained Boutar without indicating what he was accused of.
The arrests came two days after the arrest of tycoon Kamel Eltaief, former top Ennahdha figure Abdelhamid Jelassi and political activist Khayam Turki.
Many Tunisians saw Eltaief, a former confidant of ousted president Zine El Abidine Ben Ali, as a symbol of corruption in the North African nation.
His arrest comes amid a spike in prosecutions against politicians, journalists and other rivals of Saied, often in military courts, since the president's dramatic move against parliament and the Ennahdha-backed government in July 2021.
Since then, Saied's opponents have accused him of bringing back authoritarian rule in the birthplace of the 2011 Arab Spring uprisings.
The UN rights chief on Tuesday expressed alarm over a deepening crackdown in Tunisia.
"UN High Commissioner for Human Rights Volker Turk today expressed his concern over the deepening crackdown against perceived political opponents and civil society in Tunisia, including attacks on the independence of the judiciary," Turk's spokesman Jeremy Laurence told reporters in Geneva.
"Since Saturday, at least nine people, including former civil servants, have been reportedly arrested and some detained, on security and graft charges," he said.