Argentine authorities have searched a number of properties as part of an investigation into an alleged bribery scheme that may involve high-ranking officials, Reuters reported.
Authorities seized mobile phones and a money counting machine during a raid on the home of Diego Spagnolo, who until this week headed the agency for people with disabilities.
Milley's government earlier this week fired Spagnolo "as a preventive measure."
Local media have released audio recordings in which a voice similar to Spagnolo is heard discussing bribery at the agency. No details were given about when or in what context the recordings were made.
In them, Spagnolo is heard saying, "They are cheating my agency". He implies that Karina Milley, the president's sister and chief of staff, was taking bribes, and claims that he spoke to the president and "they didn't decide anything".
Government officials have not confirmed the authenticity of the recordings, and the president has not commented publicly on the matter. The chief of staff said that Milley said Spagnolo never mentioned the alleged bribe.
The scandal comes at a delicate time for Milley, who has faced a series of legislative setbacks in Congress this week, including an attempt by lawmakers to override a presidential veto on an increase in financial aid for the disabled.
The administration is preparing for midterm elections in October, which are largely seen as a referendum on Milley's austerity and market reforms.
The investigation, ordered by a federal judge, has included searches of a number of properties, including the disability agency, a pharmaceutical company and some private homes.