President Yoon Suk Yeol is expected to name a new presidential chief of staff Sunday at the earliest in what would be his first move to overhaul state affairs after a resounding defeat in this week's parliamentary elections, sources at the presidential office said Saturday.

After his party's crushing defeat in Wednesday's parliamentary elections, Yoon has delivered a message through his chief of staff that he will "humbly uphold the people's will" shown in the opposition's landslide victory in parliamentary elections.

The opposition bloc, led by the main opposition Democratic Party, won 192 seats in the 300-member National Assembly, while the ruling bloc led by Yoon's People Power Party (PPP) secured only 108.

Senior government and presidential officials are likely to be replaced, after Prime Minister Han Duck-soo, presidential chief of staff Lee Kwan-sup and all the senior presidential secretaries offered to resign Thursday.

Yoon's staff members have been praised for their job performance but partially blamed for the controversy surrounding the appointment of former Defense Minister Lee Jong-sup as ambassador to Australia.

The presidential office's poor handling of the controversy, which centered on allegations Lee was essentially given an excuse to flee the country while under investigation over a Marine's death, was widely cited as one of the factors that contributed to the ruling party's election defeat.

Potential candidates for presidential chief of staff include PPP Rep. Chang Je-won and Kim Han-gil, chief of the Presidential Committee of National Cohesion.

Some of the names being mentioned as the next prime minister nominee include Reps. Joo Ho-young and Kwon Young-se of the PPP.

Yoon is also expected to replace several ministers and reorganize the presidential office as part of efforts to overhaul government operations. (Yonhap)