South Korean President Park Geun-hye, engulfed in an influence peddling scandal, said if she was impeached she would wait for a court to uphold the decision, an official of her party said on Tuesday, signaling a political crisis could drag on for months.

Parliament is expected to hold a vote on her on Friday, but even if the opposition wins the two-thirds majority needed for impeachment, the vote must be upheld by the Constitutional Court, a process that could take months.

Park met leaders of her Saenuri party and top official Chung Jin-suk later said the president was willing to accept her party's proposal for her to step down in April, but gave no indication that was willing to resign immediately.

"She will fight really hard to overturn at the Constitutional Court," said Rhee Jong-hoon, a political commentator at iGM Consulting.

"And if the motion is overturned? She will remain in office until her term is finished. Nothing matters after the Constitutional Court rules against the impeachment bill."

Park, whose term officially ends in February 2018, could become South Korea's first democratically elected leader to leave office early in disgrace.

Her comments indicated she had not changed her mind in the face of intense pressure for her to resign immediately.

"If the impeachment proceedings take place, and the motion is approved, I will observe the process taken by the Constitutional Court and calmly go along with what's right for the country and the people," Chung quoted Park as saying

The three opposition parties need at least 28 members from Park's Saenuri Party for the impeachment bill to pass with a two-thirds majority. At least 29 of them are believed to be planning to vote for the bill, members of a breakaway faction said.

Park is accused of colluding with a friend and a former aide to pressure big business owners into paying into two foundations set up to back her policy initiatives.

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

In televised remarks last week, Park offered to step down and asked parliament to decide how and when she should leave office.

Opposition parties rejected the proposal, calling it a ploy to buy time and avoid being impeached, and vowed to push ahead with impeachment.

Protesters have also been marching to demand she resign.