A court sentenced Abd Allah Zouari, 51, on Friday to nine months in jail for violating an order that banned him from leaving the southern coastal town of Zarzis where he is from, the Tunisian Human Rights League said in a statement.
"The league denounces the sentence against Abd Allah Zouari as unfair and demands his immediate release," the group added.
Zouari worked as journalist for al-Fajr weekly, published by the now-banned Nahda Islamist party, before he was jailed in 1991 for dissident activities in the North African country.
The government said he was never accredited to work as a journalist and that he was jailed for 11 years for "terrorist activities" after getting a fair trial.
Released in June 2002, he was sent back to jail two months later and was freed last November along with three other political prisoners as part of an amnesty to mark the 15th anniversary of President Zine al-Abidine Ben Ali's accession.
Human rights groups at home and abroad accuse Ben Ali's government of harassing dissidents, rights activists and muzzling the press to stamp out dissent.