His death was announced by the government-run news agency Télam. His son José Martínez de Hoz said Mr. Martínez de Hoz had been ill and had probably died of a heart attack.

Mr. Martínez de Hoz, a former law professor, was in charge of Argentina’s economy from 1976 to 1981. Initially, he was praised by international bankers, including David Rockefeller, for his free-market policies, designed to combat Argentina’s hyperinflation, but was condemned by Argentine businessmen for the nation’s subsequent economic collapse.

Mr. Martínez de Hoz oversaw Argentina’s financial deregulation in 1977, which drew record inflows of capital from speculative investors.

“He’s identified as most responsible for Argentina’s deindustrialization,” said Sergio Berensztein, a political consultant with the independent research firm Poliarquía in Buenos Aires. “The bullet that blew up the policy was when Ronald Reagan was elected and the U.S. Fed increased interest rates dramatically.”

After Argentina returned to democratic rule in 1983, Mr. Martínez de Hoz was under arrest for two and a half months on suspicion of involvement in the kidnapping of two prominent businessmen. He was the first civilian government official to be held for abuses committed during the rein of the military junta.

He was accused of fraud for burdening the country with foreign debt, and criticized for the government’s purchase in Swiss francs of the privately owned Italo-Argentine Electric Company, where he had been a director.

However, Mr. Martínez de Hoz was shielded from the courts by President Carlos Saúl Menem’s blanket amnesty of those involved in the so-called Dirty War. He was pardoned by Mr. Menem on Dec. 30, 1990.

That amnesty was ruled unconstitutional and overturned by the Supreme Court in 2005, and an investigation into Mr. Martínez de Hoz’s role in the kidnapping of the businessmen, Federico Gutheim and his son Miguel — whose cotton export company, Sideco, was said to have been coerced into deals that favored the dictatorship — was revived in 2006. Mr. Martínez de Hoz, who was arrested in 2010 and held at home until his death, denied the accusations.

José Alfredo Martínez de la Hoz, familiarly known as Joe or Josecito, was born on Aug. 13, 1925, into an aristocratic family of wealthy landowners. In addition to his son José, he is survived by another son, Marcos; a daughter, Elvira; and 11 grandchildren.

Mr. Martínez de Hoz, who studied at Oxford, was appointed economics minister days after Gen. Jorge Rafael Videla toppled the government of Isabel Perón, the widow of the three-time president Gen. Juan Domingo Perón. General Videla is now in prison serving multiple life sentences for human rights abuses.

As part of the dictatorship’s so-called National Reorganization Process, Mr. Martínez de Hoz conceived and imposed a plan called Tablita, or little table, to let the peso depreciate steadily against the dollar. The era of plata dulce, or sweet money, ushered in by Tablita, ended in collapse, plunging Argentina into a deep recession in 1981.

Mr. Martínez de Hoz was also accused of using government funds on speculative deals, and Argentina’s foreign debt soared under his stewardship because of speculative deals with companies and International Monetary Fund loans. A federal court found him guilty in 1985 of “economic subversion” and froze $1 million of his assets, but he did not go to prison because of the court’s prior agreement when the trial began in 1983.

Strikes were banned during Mr. Martínez de Hoz’s tenure. A government investigation after Argentina’s return to democracy in 1983 found that military squadrons had seized as many as 30,000 people, including hundreds of labor activists, and secretly had them tortured and executed.

“He was among the civilians who laid out plans, alongside the armed forces, for what was an oppression of the people,” said Estela de Carlotto, the president of Grandmothers of the Plaza de Mayo, a human rights group formed in 1977 that focuses on identifying grandchildren of so-called disappeared people, who were kidnapped and appropriated by military families.

Mr. Martínez de Hoz never expressed remorse for his role in the dictatorship.