Last week acting Chief Justice Lee Jung-mi drew the line, saying the court would not reschedule hearings for witnesses who fail to show up without good reason.

Over the weekend, reports emerged that some 2,000 audio files submitted by the prosecution to the court could change the course of the proceedings in Park's favor. The files include phone conversations had by Ko Young-tae, a former associate of Park's close friend Choi Soon-sil.

Ko triggered Park's impeachment by exposing allegations that Choi abused her ties to the president to extort money from conglomerates.

In some of the phone conversations, Ko appears to be plotting to overtake a nonprofit foundation allegedly established by Choi with the government's financial support, and use it for personal gain.

"If necessary, some of the people in the audio files have to be called to the court," said the source working with Park's team of legal representatives. "We've looked into some of the files, and they've been a big help in understanding the essence of this case. I'm certain they'll have a huge impact going forward."

A parliamentary panel serving as the prosecution in the trial dismissed the files as irrelevant to the charges against Park.

"Whether Ko tried to take control of the foundation or not, it has nothing to do with the grounds for the president's impeachment," said an official working with the panel.

For Park, delaying the proceedings beyond March 13 could work to her advantage because only two justices will need to reject her impeachment to reinstate her.

There are nine justices serving on the Constitutional Court bench, but one has retired, with another justice set to retire on March 13. At least six justices must uphold the impeachment to remove Park from office. (Yonhap)