BUENOS AIRES — Argentines are not used to seeing powerful people in handcuffs.

Yet in recent months at least five prominent former officials, including a vice president and a former planning minister, have been taken into custody to await trial on corruption charges. Several allies from the private sector who stand accused of misappropriating public funds have also been locked up.

The detentions come as President Mauricio Macri has vowed to upend Argentina’s culture of impunity in graft cases by reforming the penal code, making government contracting more transparent and carefully tracking the assets of public servants.

But his government is not exactly claiming credit for the crackdown underway, which so far has netted only political opponents, leading to accusations that Mr. Macri is using the judicial system to neutralize the opposition.

“Never in the history of Argentina have we had as many important people detained,” the justice minister, Germán Garavano, said in an interview. “The question we have to ask ourselves as we look to the future is whether this represents a change, a profound reform or merely a reaction to a public outcry right now. We’ll get that answer in a few years.”