Presidential Chief of Staff Chung Jin-suk said a bill that could be deemed unconstitutional should be vetoed by the president, in reference to the opposition-pushed bill on a special counsel investigation into a military report on last year's death of a Marine.

Appearing in front of the parliamentary house steering committee on Monday, Chung said the right to request reconsideration of a bill is part of the president's authority, as well as duty. He said failing to exercise the right despite a bill's unconstitutionality would be dereliction of duty on the president's part.

The chief of staff said that as investigation and indictment fall within the authority of the executive branch, headed by the president, the appointment of a special counsel recommended solely by the opposition would go against the principle of division of powers.

Chung said with the Corruption Investigation Office for High-ranking Officials(CIO) and the prosecution conducting their investigations, it would not be considered late to table a bill on the special probe even after the ongoing investigations.

He then emphasized that the essence of the case is insubordination by Col. Park Jung-hun, who had led the Marine Corps' initial probe, against then-defense minister Lee Jong-sup's order to defer a transfer of case files to the civilian police.