Argentina's Congress has approved a law overhauling an intelligence agency under fire from the president as well as the opposition.
The measure comes after President Cristina Fernandez said the agency was out of control and suggested a top spy could have been involved in the death of a special prosecutor.
Opposition lawmakers said the revamp does not go far enough.
Argentina has been shaken by the January 18 death of Alberto Nisman, who alleged that Ms Fernandez and her allies shielded Iranian officials accused of masterminding the 1994 bombing of a Jewish community centre in Buenos Aires.
She denies that, but polls say many Argentines suspect officials had some hand in the death.
Her aides suggest he was killed in a plot to destabilise the government.
A federal judge has dismissed a prosecutor's allegations that Ms Fernandez tried to cover up the alleged involvement of Iranian officials in the 1994 attack.
Judge Daniel Rafecas said the documents originally filed by Mr Nisman failed to meet "the minimal conditions needed to launch a formal court investigation".
Mr Nisman had filed the complaint days before he died on January 18 under mysterious circumstances.
Tens of thousands of Argentines marched through the capital last week demanding answers over the death a month after he was found in his bathroom with a bullet in his right temple.
The president initially suggested the 51-year-old prosecutor had killed himself, then did an about-face a few days later, saying she suspected he had been murdered.
Authorities say they are investigating the possibility of suicide or homicide.