The trial of ousted Tunisian leader Zine el Abidine Ben Ali, in exile in Saudi Arabia, will start in his absence on June 20, interim Prime Minister Beji Caid Essebsi told Al-Jazeera Monday.
"I am announcing it for the first time, the trial will start on the 20th", Essebsi told the television channel.
Ben Ali and his associates were facing more than 90 charges, he added.
He also said Saudi authorities had not responded to Tunisian requests to hand over the former president.
Ben Ali fled Tunisia in January following a revolt against his 23-year rule. Family members say he suffered a stroke in February and he has made no public appearances.
Tunisia's new authorities are preparing to try him and his wife Leila Trabelsi on drugs, guns and graft charges in absentia.
Tunisian authorities have said the first charges will relate to the discovery of cash, weapons and drugs in presidential palaces, including almost two kilogrammes (4.4 pounds) of narcotics, thought to be cannabis, and ê27 million in cash.
These finds form the basis of only two of the dozens of ongoing inquiries into the first couple, their family and the regime's former ministers and officials.
Authorities have said they are also looking into cases of murder, abuse of power, trafficking of archaeological artifacts and money laundering.
A statement released last week by Ben Ali's French lawyer, Jean-Yves Le Borgne, denounced the investigation and trial in preparation.
"The searches carried out in his official and personal offices are just set-ups designed to discredit him," said the statement from Leborgne.
"The trial that Tunisia is preparing against him is just a masquerade, whose only aim is to illustrate a symbolic break with the past."
Ben Ali also said through his lawyer that he had no property or assets in France or anywhere else abroad.
Several European countries have nevertheless said they have frozen assets belonging to Ben Ali and his entourage.
Tunisia's interim administration has called for the former president to be extradited from Saudi Arabia along with his wife.
The Tunisian revolution was the first and so far the most successful of a string of uprisings against autocratic rulers in the Middle East and north Africa, which have come to be known as the Arab Spring.
Egypt also began a programme of democratic reform after the fall of Hosni Mubarak, but Libya and Yemen have fallen into civil conflict and pro-democracy protests in Bahrain and Syria face brutal repression.