The ruling Minjoo Party and proxies swept to victory in a landslide in Wednesday's general election to secure more than 180 seats in the National Assembly.
President Moon Jae-in has gained solid parliamentary support on the strength of the government's response to the coronavirus epidemic.
The Minjoo Party won 163 out of 253 constituencies across the country, while the main opposition United Future Party took only 84.
Adding about 17 to 20 proportional representation seats won by proxy minor parties like the Together Citizens' Party and Open Democrats, the ruling party won about 180 seats to achieve a clear majority for the first time in 16 years.
Minjoo weathered the corruption scandal surrounding fly-by-night Justice Minister Cho Kuk as well as the government's dismal economic record, winning over 100 out of 121 constituencies in the Seoul metropolitan area, while the UFP won fewer than 20 as it was routed everywhere except the affluent Gangnam and Yongsan areas.
It was the biggest victory by the ruling party since 1987.
The UFP held on to its traditional strongholds of South Gyeongsang and Gangwon provinces, but in a devastating blow both party leader Hwang Kyo-ahn and party heavyweights Oh Se-hoon and Na Kyung-won lost their seats to Minjoo challengers who are relative newcomers.
Hwang saw his presidential ambitions wiped out by losing against former prime minister Lee Nak-yon in the bellwether Jongno constituency in the heart of Seoul.
He resigned as party leader soon after his defeat.