On Tuesday, Choi refused to testify as a witness in the trial at the highest court, citing she was under investigation in a scandal where she was criticized for using her ties to the president to extort money and favors from big firms and use them as her personal ATMs.

So the Constitutional Court delayed the examination of Choi as a witness to 10:00 a.m. on Monday, adding, "If Choi does not appear in court, she will be forced to stand as a witness."

On the same day, the court plans to call in President Park's former chief policy aide Ahn Jong-beom as a witness to proceed with the trial on the widening influence-peddling scandal where Choi, with no official title or security clearance, also meddled in state affairs.

After being impeached by parliament last month for her involvement in the massive scandal, Park has said she will prove her innocence in the trial but has yet to appear in court. (Yonhap)