An independent commission set up to investigate crimes by the Tunisian state has accused President Beji Caid Essebsi of complicity in torture and his predecessor Zine al-Abidine Ben Ali of corruption.

A report by the Instance Verité et Dignité (IVD), or Truth and Dignity Commission, details the 92-year-old Essebsi’s alleged responsibility for crimes committed while serving as a minister in the regime of Habib Bourguiba.

It also alleges extensive corruption by the former president Ben Ali, his extended family and wider network, including the misuse of public funds, and human rights violations including enforced disappearances and torture committed under his rule.

Tunisian authorities have frequently attempted to impede the work of the Truth and Dignity Commission since its creation in 2013. It is tasked with exposing decades of crimes committed between the last year of French rule in 1955 and the 2011 uprising that overthrew Ben Ali.

The body, modelled on South Africa’s Truth and Reconciliation Commission, was designed to provide evidence to break with the country’s past and help build a brighter future following the 2011 uprising, which ended decades of autocratic rule.

The IVD revealed in December that it had uncovered 62,720 cases of abuse, and has since referred at least 173 cases to a network of specialised courts intended to trial perpetrators, including former officials.

The commission alleges that Essebsi oversaw mass arrests and show trials against Bourguiba’s political opponents following an attempted military coup in 1962, where Essebsi’s brother Salah El-Din Caid Essebsi was appointed the government’s defence lawyer in military trails that sentenced people to death or life imprisonment.

Essebsi is one of many ministers to criticise the commission’s work, stating last year that he is “against settling scores of the past”. His office did not respond to a request for comment on the report’s findings when contacted by the Guardian.

The report states that those “acting on behalf of or under the protection of state agencies” bear responsibility for crimes committed on their watch, a nod to Essebsi’s tenure as minister of the interior when torture was rampant, and details the killing of peaceful protesters during the uprising that toppled Ben Ali.

The exiled former president, now living in Saudi Arabia, was previously sentenced in absentia to 20 years in prison for the protesters’ deaths. He and several members of his family have been sentenced for corruption in multiple casesmost recently since the 2011 uprising, in 2017 when they were handed an additional 10-year sentence for misusing a state-owned nature park.

The report also includes findings from interviews with 1,782 Tunisian resistance fighters of crimes committed by occupying French forces before the end of French rule in 1956, and demands that France remove a military cemetery in Gammarth and replace it with a memorial.

But the commission’s efforts to detail past crimes and bring those who committed them to justice have often been impeded by the government, including through a law originally proposed by Essebsi to allow officials previously accused of corruption to strike opaque deals with the authorities in exchange for immunity, and return to work.

The report lists government efforts to prevent the IVD accessing national archives to find evidence of past crimes, as well as pressure from a union of security service workers who rejected efforts by the commission to refer members to trial.

It also outlines a proposed overhaul of the Ministry of the Interior and demands extensive reforms to bring transparency and prevent the security services committing further crimes. Amnesty International and other human rights groups have frequently criticised the Tunisian government’s unwillingness to reform its powerful security services since the 2011 revolution.

“Tunisia’s authorities must demonstrate a clear political will to tackle impunity by protecting and enabling the specialized chambers dealing with transitional justice to carry out their work,” said Fida Hammami of Amnesty International in Tunis. “The government must ensure that security sector members cooperate with transitional justice trials and that judges, victims and witnesses are protected from any act of intimidation or reprisal.”

Tunisia will hold parliamentary and presidential elections later this year. Earlier this month, Essebsi called for changes to the country’s constitution to grant further powers to the president.