The human rights group Amnesty International has accused Tunisia of systematic human rights abuses and arbitrary arrests of opponents of the government.
In a new report, Amnesty said that for more than a decade the Tunisian authorities had used the security issue to curtail the basic rights of hundreds of political and other prisoners.
"In Tunisia opponents or perceived opponents of the government are subjected to abuse within a justice system resembling one from a Kafka novel," Amnesty UK director Kate Allen said.
The group urged Tunisia to urgently reform its justice system, release all prisoners of conscience and guarantee fair trials for all the accused.
Amnesty said that its 40-page report - the first major document on the country since 1988 - revealed a repressive cycle of human rights abuse.
It said that since 1999 scores of civilians had been tried in military courts, with many receiving long prison sentences.
"People are arbitrarily arrested and held out of sight of families and lawyers for long periods," Ms Allen said.
"Confessions are coerced out of detainees, at trial defendants' files are confiscated from lawyers or tampered with, and political prisoners are subjected to a harsh prison regime, including solitary confinement," she added.
The report said that even after release, many political prisoners were subject to "administrative control", being monitored, harassed and frequently re-arrested.
It also said that overcrowding and poor sanitary conditions in the country's prisons was the norm, with some inmates reporting that up to 150 people had to share one toilet.