A woman walks behind a poster that reads "AMIA (Jewish community center). Nisman's death. Disolve the SIDE (Secretary of Intelligence)" in Buenos Aires January 26, 2015. [Photo/Agencies]

Fernandez, 61, said the new "Federal Intelligence Agency" would have a director and deputy, and only a few in government would have access to the agency heads, apparently a critique of a system where many in Congress have contact with intelligence officials.

In her two letters the last week, Fernandez suggested Nisman's death was a plot against her government possibly orchestrated by intelligence services, which had fed false information to Nisman.

In her first letter, published Jan. 19, she suggested that Nisman committed suicide. Three days later, however, she did an about-face, suggesting that he had been killed.

Argentina's political opposition criticized Fernandez's latest comments.

Before there are any reforms to the intelligence services, the government "should explain the 11 years it has managed" them, opposition lawmaker Margarita Stolbizer told Todo Noticias.

"The speech was filled with imprecise (statements) and lies," Stolbizer said. "She did not give answers to the doubts about this government nor about the content of Nisman's denouncement."

Employing the fiery rhetoric she is known for, at the end her televised speech, Fernandez said she had a message for her countrymen.

"I will not be extorted, I am not afraid" of being cited by judges or denounced by investigators, she said. "They will not make me move even a centimeter from what I have always thought."