In addition to People Power Party (PPP) leader Han Dong-hoon, Prime Minister Han Duck-soo and a string of senior aides also offered to step down, local media said.
The result has turned Yoon into a lame duck president for the remaining three years in office, just as the country is facing challenges including a weak economy and an increasingly aggressive North Korea, experts said.
“There will be even more extreme confrontation between Yoon and the opposition in the next parliament, especially with the election of candidates vowing a very hawkish stance on his administration,” said Shin Yul, professor of political science at Myongji University.
“It won’t be easy for people to see bipartisan cooperation,” he told AFP.