Conservatives from Mr. Lee's party captured more than half the 299 assembly seats, while candidates from two smaller parties added another 30 seats to the conservative total.
One of the president's political allies running for office, Chung Mong Joon, one of Korea's wealthiest men, defeated Chung Dong Young, whom Lee had trounced in the presidential election in December. Chung Mong Joon inherited his controlling stake in Hyundai Heavy Industries, the world's largest shipbuilder, from his father Chung Ju Yung, founder of the Hyundai empire.
Conservatives dominated every region except the southwest, the springboard of the rise to power of former president Kim Dae Jung, who initiated Korea's Sunshine policy of reconciliation with North Korea during his term from 1998 to 2002.
Candidates had to battle apathy among voters, who had long expected conservatives to take over the assembly. Only about 44 percent of eligible voters cast their ballots one day after crucial talks in Singapore between US nuclear envoy Christopher Hill and his North Korean counterpart, Kim Kye Gwan.