Peruvian Prosecutor Jose Domingo Perez filed charges against Kuczynski for money laundering in an organized crime group, Peruvian media reported.
"He is totally calm," the former president's lawyer Julio Mindolo told reporters. "He is confident the situation will be resolved and that no one can link him to any acts of corruption."
An investigation into Kuczynski has reportedly been ongoing for the last five years.
Local media indicated that three more people are subject to the investigation, facing prison terms of 35, 26 and 11 years.
During the hearing, the judge reportedly dismissed the prosecutor's petition to extend exiting ban on Kuczynski, ruling that such a move would be a violation of the former president's right to freedom. Kuczynski spent 36 months under house arrest from 2019-2022, after which he was released and attended court as a free man.