President Park Geun-hye is likely to nominate a new prime minister early this week to push ahead with her reform drive on fresh momentum following the local elections last week.
The president's surprising appointment of a new press secretary on Sunday also raised views that a reshuffle of presidential aides is impending.
Park on Sunday morning named Yoon Doo-hyun, president of YTN Plus, a subsidiary of cable news network YTN, as the new presidential senior press secretary.
Yoon, a former journalist and managing editor of the YTN newsroom, replaces Lee Jung-hyun, who offered to step down on Saturday. Lee, one of Park's close aides, offered to resign on Saturday amid growing speculation that he would run for a by-election on July 30.
"President Park Geun-hye has named Yoon Doo-hyun, president of YTN Plus, as successor to senior secretary Lee Jung-hyun," said presidential spokesman Min Kyung-wook.
"Yoon has demonstrated his balanced thinking and sharp analysis while serving as the political desk editor and managing editor at YTN.
"He was appointed because he was believed to be the right person to be a communicator in explaining government reform policies, and in seeking understanding and cooperation from the people," he said.
The announcement came after Park reiterated her determination to push forward with her reform agenda in her Memorial Day speech on Friday. Her pledge also came after her ruling party avoided a crushing defeat in the local elections last week despite widespread criticism of her government in the wake of the April ferry disaster.
Cheong Wa Dae has been searching for a new candidate for the nation's No. 2 post after Ahn Dae-hee, a former star prosecutor, dropped his nomination last month amid spiraling speculations that he received favors. Park is expected to choose a well-reputed person who has no ties to power, politics or government to assure the public that the nominee has no ethical lapses.