A Tunisian man has been sentenced to death on charges of insulting the president and assaulting state security through posts on social media, the head of the Tunisian League for Human Rights and his lawyer said on Friday.

The ruling is unprecedented in Tunisia, where restrictions on free speech have been tightened since President Kais Saied seized almost all powers in 2021.

The man sentenced, 56-year-old day labourer Saber Chouchane, is a regular citizen with limited education who was simply writing posts critical of the president before his arrest last year, his lawyer, Oussama Bouthalja, told Reuters.

"The judge in the Nabeul court sentenced the man to death over Facebook posts. It is a shocking and unprecedented ruling," Bouthalja said.

The judgment has been appealed, he added. The justice ministry was not immediately available to comment.

Though courts have occasionally handed down death sentences in Tunisia, none have been carried out for more than three decades.

"We can't believe it," Jamal Chouchane, Saber's brother, told Reuters by phone. "We are a family suffering from poverty, and now oppression and injustice have been added to poverty."

The sentence immediately sparked a wave of criticism and ridicule on social media among activists and ordinary Tunisians.

Many described the ruling as a deliberate attempt to instil fear among Saied's critics, warning that such harsh measures could further stifle free expression and deepen political tensions.

Since Saied dissolved the elected parliament and started ruling by decree, Tunisia has faced growing criticism by rights groups over the erosion of judicial independence. The opposition called Saied's power grab a coup.

Most opposition leaders, whom the president has labelled as traitors, are imprisoned on various charges.