South Korean opposition parties said on Friday they will hold a parliamentary impeachment vote on scandal-tainted President Park Geun-hye next week, while her own party remains undecided on whether to force her out of office.

Park has offered to resign and asked parliament on Tuesday to decide how and when she should step down over the influence peddling scandal but the opposition has rejected it as a delaying tactic to avoid impeachment.

If Park is forced out of office or resigns, she will be the first democratically elected South Korean president not to serve a full term. A large rally is expected on Saturday, the sixth weekend protest in succession, calling on her to resign immediately.

The three opposition parties, with a combined 165 seats in the 300-member parliament, can bring the impeachment but will need some members from Park’s Saenuri Party to bring the vote to the two-thirds majority required to pass the bill.

“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.

“The motion will be proposed today. It will be reported to the plenary session on Dec 8 and we will bring the impeachment motion to a vote on Dec 9,” he said.

Park is accused of colluding with a friend, Choi Soon-sil, who has been accused of abuse of power, to put undue pressure on conglomerates to contribute money to foundations that were set up to promote her policy initiatives.

Park has denied wrongdoing but has apologized to the nation.

Some Saenuri members had earlier said they would join the opposition parties to impeach Park but changed their position after Park offered to quit, saying she should be given the chance to step down of her own accord 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.

It was not clear whether there would be the needed 28 Saenuri members to support the vote. There are seven non-party affiliated members who are expected to give their backing.

Some opposition members have said a failed impeachment could vindicate Park’s claim to have done nothing to benefit personally and help her survive politically.

“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.

If it passes, the Constitutional Court has 180 days to approve or reject it. If approved, a new election must be called in 60 days to elect a new leader for a full five-year term.

Park has come under intense pressure to step down, with hundreds of thousands of people streaming into the streets demanding her resignation at successive weekend rallies, which have remained peaceful.

Her approval rating remained at a record low of 4 percent, according to a Gallup Korea opinion poll released on Friday. Gallup Korea, based in Seoul, is not affiliated with U.S.-based Gallup Inc.