The presidential office Cheong Wa Dae on Friday said a special inspector's alleged leak of information over his probe into a presidential aide would constitute a "grave violation of the law," if it turns out to be true.

The remarks came a day after Lee Seok-su, a special inspector looking into the allegations of corruption involving Woo Byung-woo, senior presidential secretary for civil affairs, submitted a petition with the state prosecutors' office to seek a formal investigation.

Lee himself has been mired in a controversy after local broadcaster MBC reported Tuesday that he illegally leaked information about his investigation into Woo to an unspecified reporter via social media.

By law, a special inspector can face a prison sentence of up to five years for leaking information related to ongoing work.

"(The alleged leak of information, if it is true) is a grave breach of the law, and a matter that can't be condoned," senior presidential secretary for public affairs Kim Sung-woo told reporters.