South Korea's top prosecutor on Wednesday said an ongoing probe into allegations surrounding Justice Minister Cho Kuk's family is being conducted in an appropriate manner.

Replying to reporters on the sidelines of an international anti-drug conference, Prosecutor General Yoon Seok-youl said the investigation "is being conducted in accordance with the (appropriate) procedure."

Yoon's remarks come amid criticism on the appropriateness of ongoing probes into corruption allegations involving Cho's wife and the couple's two children. Cho's wife is alleged of forging a university award to help the couple's daughter gain admission to medical school, while the three of them are suspected of a dubious investment in a private equity fund.

Following dozens of raids last month, prosecutors on Monday raided Cho's residence in southern Seoul for 11 hours, an unprecedented move involving an incumbent justice minister.

Prosecutors are known to have secured computer hard drives and numerous documents.

The justice minister, who oversees the prosecution, has denied claims against his family and pledged not to intervene in the probes over his family. However, he recently said his family is going through a "difficult time," adding he is "seriously" thinking about taking legal action against what he called a malicious media report.

Cho, a former presidential aide, is seen as the key figure in carrying out President Moon's judicial reform drive. (Yonhap)