Argentina president bows to pressure in graft scandal
Macri had been under fire for three weeks after details emerged of the deal signed last year.
Critics said his government effectively wrote off part of the debt run up by the Argentine postal service during a period when it was under the private control of a business run by his father Franco Macri.
The president told a news conference on Thursday that he had ordered his government to “start again from scratch” with negotiations over the deal.
He denied any detailed knowledge of the terms of the previous deal, which his opponents said unfairly benefited his father.
A prosecutor on Tuesday filed a case calling for Macri to face a judicial investigation over an alleged financial conflict of interests.
Macri has been trying to steer Argentina out of recession since taking over as president in December 2015.
He faces a key political test in October this year when the country holds legislative elections.