The embattled president already appointed two new senior secretaries for civil affairs and public relations Sunday amid mounting calls for a sweeping personnel reshuffle of both her office and Cabinet.

With the latest appointments, Park replaced three of her 10 senior secretaries, as well as her chief of staff.

"(Han) has been appointed as he is well suited to assist the president from the citizens' perspective and stably manage state affairs given his deep knowledge and various experience, as well as the values of reconciliation and inclusion he has upheld," presidential spokesman Jung Youn-kuk told reporters.

The 74-year-old Han, a former four-term lawmaker, served as a chief of staff to late liberal President Kim Dae-jung who ran the country from 1998 to 2003. In 1998, he also served as head of a tripartite panel consisting of representatives of employees, employers and the government. 

Hur, the new senior secretary for political affairs, formerly worked as a journalist for several local media outlets including The Kyunghang Shinmun and local broadcaster KBS. He also served as a lawmaker from 2008 to 2012.

On Wednesday, Park tapped Kim Byong-joon, a former policy adviser to the late liberal President Roh Moo-hyun, as new prime minister and nominated the new ministers of finance and public security. Opposition parties, however, oppose what they call the "unilateral" nominations.

At the center of the massive scandal gripping the country is Choi Soon-sil, whom critics portray as the "eminence grise" of the Park administration.

Choi is alleged to have used her decadeslong ties to the president to meddle in state affairs, particularly presidential matters, such as Park's wardrobe, public speeches and even the selection of presidential secretaries.

The 60-year-old woman is also suspected of having peddled undue influence in the creation and operation of two nonprofit foundations dedicated to promoting Korean culture and sports. She is being investigated to see if she misappropriated money from the foundations.

The scandal has sent Park's approval rating plunging to a woeful single digit and prompted nationwide calls for her resignation. (Yonhap)