President Park Geun-hye, mired in a high-profile corruption scandal centering on her confidante, remained silent Thursday, as political parties barreled towards an impeachment showdown.

Since she signaled her determination to accept an impeachment trial during talks with the leaders of the ruling Saenuri Party Tuesday, the embattled leader has kept a wait-and-see stance, failing to deliver on a pledge to hold a press conference to explain her stance on the scandal.

On Friday afternoon, the National Assembly is set to vote on the historic impeachment motion -- the first since 2004 -- the passage of which will open the adjudication process at the Constitutional Court, which could take up to 180 days.

The passage of the motion requires votes from at least two thirds of the total 300 lawmakers. The lawmakers of the main opposition Democratic Party remain confident about the prospect of the motion's passage, vowing to resign as legislators if it is voted down.

In a last-ditch effort to thwart the impeachment drive, loyalists to Park within the ruling party reportedly asked Park to publicly declare her voluntary departure by April next year. But Park appeared unwilling to issue another public statement, sources said.    

"Park will calmly watch the (impeachment) vote and respond appropriately to the unfolding situation," a presidential official told Yonhap News Agency, declining to be named. "Though she may look nonchalant, (the current situation) might be weighing heavily on her mind."

The presidential office Cheong Wa Dae is expected to issue a statement after the vote on the motion, observers said, given that any public message before the vote could further inflame public sentiment.

If the motion is passed, Park is likely to remain in office until the court delivers its ruling on the highly charged case, observers said. The presidential office has repeatedly said that it would "follow the due legal process" in an indication that Park would not resign amid the trial.

However, if the motion is voted down, Park is expected to pursue the scenario that the ruling party previously suggested -- her "orderly" departure by the end of April with a presidential election to follow two months later.

On Wednesday, Saenuri Party leader Lee Jung-hyun said Park should officially declare she would step aside by April next year even if the impeachment motion is rejected. (Yonhap)