South Korea's main opposition Democratic Party on Friday announced that the discussion on carrying out a special probe into the Choi Soon-sil scandal will temporarily be suspended until the ruling party also agrees to the plan to sack presidential aides linked to wrongdoing.

On Thursday, South Korea's three major parties kicked off discussions on nominating a special prosecutor to look into the allegation that Park's confidante exercised influence on state affairs, along with other illegal acts including the suspicious raising of funds for public foundations.

The parties, however, failed to reach any resolution as they remained far apart on how to proceed with the investigation by an independent counsel.

The ruling party prefers to use the existing special prosecution system under which the president is to play a part in the selection of an independent counsel, while the main opposition has rejects that idea and calls for the introduction of a special bill to enact a special investigation.

The minor People's Party suggested an investigation led by opposition parties and civic groups, casting further cloud over the talks.

Choi, who has known the president for some 40 years, is the fifth daughter of Park's late mentor Choi Tae-min, a leader of a questionable religious group who died in 1994.

Observers said Park developed a friendship with the Choi family after her mother and then-first lady Yook Young-soo was assassinated in 1974. Park also said earlier this week that Choi helped her when she was going through very hard times while expressing her apology for the scandal.

"The Democratic Party will reconsider all negotiations in progress with the Saenuri Party," said Rep. Choo Mi-ae, the opposition head.

"Saenuri must first express an apology to the people. There must be the resignation of Woo Byung-woo, senior presidential secretary for civil affairs," Choo said. "All those who supported Choi must step down (before continuing the negotiation)."

Choo added that if the ruling party expresses a sincere commitment to normalizing state affairs the Democratic Party will also resume the talks on implementing a special investigation.

"The president has lost her ethical authority," Choo said.

"Although the Constitution stipulates the president cannot be criminally charged, she still holds a grave administrative responsibility."

An official from Saenuri, however, criticized the opposition party for leaving the negotiation, adding that an opposition-led investigation will lack political neutrality.

"The opposition party is just planning to drag the scandal out over a long period to manipulate it with political intentions," another Saenuri official said, adding it will be complicated to reach an agreement.

An independent lawmaker, meanwhile, proposed a bill on Thursday that invalidates the passports of those who leak presidential documents, aiming to bring Park's behind-the-scenes power broker back to South Korea from Germany.

Rep. Lee Chan-yeol, an independent lawmaker, said the move came as although the existing law can suspend the passports of those who committed crimes worthy of a jail term of more than three years, the regulation does not provide details, making it controversial to be applied on Choi.

Choi said she came to Germany to "protect" her daughter, adding the two are being used as pawns in political intrigue. Choi added her poor health prevents her from traveling back to South Korea for investigation at present. (Yonhap)