SEOUL, Nov. 16 (Xinhua) -- South Korean prosecutors initially announced its plan to investigate scandal-hit President Park Geun-hye on Wednesday, but the investigation is expected to be delayed indefinitely as the president's counsel requested it to minimize the number of being investigated.

The prosecution office had claimed the need for a face-to-face questioning of President Park no later than Wednesday given that it plans to indict Park's longtime confidante, Choi Soon-sil suspected of intervening in state affairs from the shadows, around Saturday.

However, the embattled president's attorney said Tuesday that the number of the face-to-face questioning should be minimized as rival political parties agreed to a bill to appoint a special prosecutor who will probe into the case independently.

Questioning the president through documents would be desirable, the attorney noted.

Prosecutors said it can investigate President Park on Thursday, but the direct questioning looks hard to be carried out by the current investigative unit of the Seoul Central District Prosecutors' Office incapable of forcing the president to be investigated.

The attorney, who is seeking to let the president avoid multiple investigations, is forecast to accept a document questioning by the current investigative unit and allow the special prosecutor to directly investigate the president after allegations prove to be true.

Under the country's constitution, a president has immunity from being criminally executed except for charges of treason and insurrection, but investigation is allowed if the indictment is suspended until the end of single, five-year term.

Opposition parties denounced the delayed investigation. Choo Mi-ae, chairwoman of the main opposition Minjoo Party, told a supreme council meeting that it was deplorable for the president's lawyer to insist on the minimized probe and document questioning when new suspicions surrounding the scandal emerge every day.

Choo, who is leading the party's campaign to let President Park resign, raised suspicions about the president's attempt to destroy evidence, saying the case cannot be concluded without investigation into the president who is suspected of having a deep involvement.

Park Jie-won, floor leader of the minor opposition People's Party, told a party meeting that the presidential office and the ruling Saenuri Party are seeking to buy time to escape from the scandal, urging the president's resignation.