South Korea's three opposition parties will vote next week to impeach beleaguered President Park Geun-hye, they said Friday.

The parties, who together control 165 seats in the 300-member parliament, would need the support of 30 members of  Park's Saenuri Party to reach the two-thirds majority required to impeach the President.

Hundreds of thousands of Koreans protested for five consecutive weekends, asking for Park to step down or face impeachment. Criminal investigators accused her of aiding the criminal activities of her secret confidante Choi Soon-Sil. 

Choi, the daughter of a deceased cult leader who mentored Park, used their close connection to coerce major Korean conglomerates to donate tens of millions of dollars to foundations she set up for personal gain and that promoted Park's policy initiatives.

Park denied wrongdoing but offered to resign on Tuesday, asking parliament to dictate the terms of her departure, but opposition parties viewed it as a cynical ploy to delay impeachment.

"The three opposition parties will pursue the impeachment through close cooperation and without wavering," a spokesman for the main opposition Democratic Party, Ki Dong-min, said.

If the opposition parties manage to sway 30 ruling party members to vote against their leader, the Constitutional Court would have 180 days to approve or reject it. If approved an election must be called in 60 days to elect a new leader for a full five-year term.

But some opposition members fear a failed impeachment vote would vindicate Park's protests of innocence.

"If the motion is voted down, it is effectively a remission of her sins," People's Party chief Park Jie-won told a party meeting on Thursday.

Wavering support for the motion

Some Saenuri members said they would support impeachment, but backed down after Park offered to resign by April.

"The president has offered to step down, so I don't get what the motive is for insisting on impeaching her when we know there's going to be uncertainties and confusion and side-effects," Saenuri leader Chung Jin-suk said at a meeting.

Park is the first sitting president to be criminally investigated. As President she cannot be charged with any criminal offense other than insurrection or treason, but she would lose that immunity once she loses the presidency.

Park approved the appointment of a special prosecutor on Wednesday, who will interview the President and be given 120 days to follow up on the findings of state investigators. She earlier said she was too busy to meet with investigators.

Protest organizers said they would proceed with protests this weekend despite her offer to resign.

aw/kl (AFP, Reuters, dpa)