President Yoon Suk Yeol speaks during a meeting on pending issues about the economy at the presidential office in Seoul, in this file photo provided by the presidential office, April 4. Yonhap

A senior official at the presidential office said Sunday it will take time to name candidates for a new prime minister and chief of staff, after the resounding defeat of the ruling party in last week's parliamentary elections.

The official told Yonhap News Agency that some media outlets have reported that the office of President Yoon Suk Yeol may announce a personnel reshuffle as early as Sunday, but "it is not physically possible."

"It needs a minimum amount of time to find and verify people," the official said on the condition of anonymity.

After the crushing defeat of the ruling People Power Party (PPP), Yoon delivered a message through his chief of staff that he will "humbly uphold the people's will."

The opposition bloc, led by the main opposition Democratic Party of Korea, won 192 seats in the 300-member National Assembly, while the ruling bloc led by Yoon's 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 most senior presidential secretaries offered to resign. (Yonhap)