South Korean President Park Geun-hye, engulfed in an influence-peddling scandal that has prompted huge rallies calling for her removal, faces an impeachment vote on Friday that could see her become the country's first democratically elected leader removed from office.

Parliament is expected to vote in favor of impeachment, with support from some members of Park's conservative Saenuri Party, but the Constitutional Court must decide whether to uphold the motion, a process that could take up to 180 days.

The parliamentary session for the vote was scheduled to begin at 3 p.m. (0600 GMT), with the secret balloting process expected to take about one hour, according to media reports.

Park, 64, is accused of colluding with a friend and a former aide, both of whom have been indicted by prosecutors, to pressure big businesses to donate to two foundations set up to back her policy initiatives.

She has denied wrongdoing but apologized for carelessness in her ties with her friend, Choi Soon-sil.

Park said this week she would await the court's ruling, signaling that the six-weeks-long political crisis marked by huge Saturday rallies calling for her ouster is set to continue.

Parliament introduced the impeachment bill on Thursday and it must be voted on within 24 to 72 hours.

If the motion passes, the Constitutional Court will determine whether parliament followed due process and whether there are sufficient grounds for impeachment, a process that will involve arguments from the two sides in public hearings.

Prime Minister Hwang Kyo-ahn, who holds what is largely a ceremonial role, would assume interim presidential powers while the court deliberates.

The 9-member court is considered conservative in its makeup but some of its former judges have said the case against Park is strong and was likely to be approved.

The Bank of Korea will hold emergency meetings to review policy measures that may be taken against any fallout from the vote, a central bank official said.

In 2004, parliament impeached then-president Roh Moo-hyun, suspending his powers for 63 days while the court reviewed the decision, which it overturned.

The stakes are high for both sides. The leaders of the two main opposition parties said their 159 members would all resign if the impeachment motion failed, taking responsibility for their inability to follow through on the demands of the public.

Park, the daughter of a former military ruler, is under intense pressure to resign immediately.

Her approval rating stood at 5 percent in a Gallup Korea poll released on Friday, a slight improvement from a record low 4 percent. The poll also showed 81 percent of respondents supported the impeachment.