The Constitutional Court will issue a ruling this week on whether the scheduled special investigation into President-elect Lee Myung-bak's alleged involvement in a 2001 financial scam is unconstitutional or not.

President Roh Moo-hyun appointed Chung Ho-young, a former chief of the Seoul High Court, as special counsel Monday to lead the probe of the President-elect. But the launch of an investigation, which is expected to start Jan. 14, depends on the court's ruling.

Chung, 60, currently serves as a lawyer for the Seoul-based law firm, Bae, Kim & Lee LLC.

Under a special bill initiated by the pro-government United New Democratic Party (UNDP) and approved by the National Assembly last month, Chung is to conduct an investigation into allegations of the alleged past misdeeds of Lee until shortly before his inauguration on Feb. 25.

Hours after the appointment, the Ministry of Justice submitted its opinion to the Constitutional Court that the law on special investigation of Lee contained unconstitutional clauses.

But the Supreme Court, which was also asked to submit am opinion on the probe, has declines to do so, court officials said, citing possible conflicts of interest.

Last week, six plaintiffs, including the President-elect's brother and brother-in-law, filed a petition with the Constitutional Court, claiming that the scope of the law contravenes the Constitution.

Two days before his election on Dec. 19, the prosecution cleared the CEO-turned presidential candidate of any wrongdoing, but pro-government and minor opposition party lawmakers passed a bill requiring an independent investigation into the allegations.

The Justice Ministry said that the law goes against the Constitution, which bans multiple investigations into the same allegations against a suspect.

It also said the law, which empowers the chief judge of the Supreme Court to name a special prosecutor, could be unconstitutional, citing the principle of the separation of power between the judiciary and the prosecution.

Constitutional Court officials said no schedule for a verdict has been fixed yet. ``But considering the urgency of the issue, we have decided to issue a ruling as early as possible,'' an official said.

Cheong Wa Dae downplayed the ministry's petition. ``Is there any past case that the Justice Ministry supported a special probe? Some critics have always called the planned special probe unconstitutional,'' Roh's spokesman Cheon Ho-seon said.

Asked about the next move of the presidential office under a possible ruling of ``unconstitutional,'' the spokesman said, ``We will state our official position if the court declares it to be so.''

Cheon added that the presidential office's internal belief was that the investigation was legitimate.