It was the first such truth-seeking body in the Arab world and has been praised as a model for other Arab countries.
Benzekri, a former Marxist, was one of many Moroccans illegally detained, imprisoned, tortured, or forcibly "disappeared" by state security forces from the 1950s to the 1990s.
The commission put the number of victims in the hundreds; most human rights activists say it is in the thousands.
Abdelhamid Amin, a former president of the Moroccan Association for Human Rights who was imprisoned with Benzekri from 1979 to 1984 and later worked closely with him in several human rights organisations, said: "Benzekri's struggle, first in prison and later in all he did for justice in this country, was an important achievement.
"We mourn his death, all the more because his work remains incomplete."
Last year, the commission issued a report naming those it judged perpetrators of abuses, outlining a reparations plan for victims and calling for institutional and legislative reforms to prevent further human rights violations.
Moroccan and international human rights groups have said the commission's efforts may be undone if the Moroccan government fails to act on the report's recommendations.