Korea's ruling party won an outright majority in Wednesday's parliamentary elections in a dramatic upset victory expected to serve as a major boon to its leader and presidential hopeful, Park Geun-hye, just eight months before the presidential vote.

With all votes counted, the ruling Saenuri Party won 152 of the total 300 seats up for grabs against the main opposition Democratic United Party (DUP)'s 127 seats, according to data from the National Election Commission.

The DUP's coalition partner, Unified Progressive Party, won 13 seats and the conservative minor opposition Liberty Forward Party five seats. Three others went to independents, according to the results.

DUP spokeswoman Park Sun-sook conceded defeat.

"The Democratic Party failed to turn public calls for punishing the current government and the ruling party into reality. We are sorry to disappoint the people," she said during a press conference. "We will deeply reflect upon the meaning of today and try ceaselessly to be reborn as a party that the people can rely on."

The ruling party said it will make sure to carry out its campaign promises.

"Until only a few months ago, widespread prospects had been that the Saenuri Party wouldn't be able to win even 100 seats," said the party's campaign committee spokesman, Lee Hye-hoon. "We will keep the promises we made to the people without fail."

The presidential office said it is grateful for the people who made "wise choices."

"The government will do its best to take care of state affairs and the livelihood of ordinary people in a stable manner and to push ahead with policies for the sake of national interests and the future," presidential spokesman Park Jeong-ha said.

The quadrennial poll was to elect a new 300-member National Assembly, but it took on extra significance as the results are likely to affect December's presidential election. It was the first time in 20 years that the two big elections take place in the same year.

The ruling party's victory came as a surprise and is expected to significantly bolster Park's standing as a presidential candidate as she is credited for overseeing efforts to rebuild the once-beleaguered party and has been at the forefront of its election campaign.

The ruling party had been in shambles until Park took over in December due in large part to perceptions it is a party primarily for the rich and privileged. The party had been widely expected to lose badly in the general elections, but it has seen its approval ratings climb after a series of reform measures under her leadership.

Park has won a seat as she ran as one of the party's proportional candidates.

One of Park's opposition rivals, Moon Jae-in, also won a seat in the port city of Busan.

The opposition DUP was once forecast to win an easy victory, riding on President Lee Myung-bak's unpopularity, driven by perceptions the gap between rich and poor has widened under his pro-business policies and the benefits of growth in big businesses have not trickled down to the working class.

The DUP chipped away at its own lead, however, by fumbling the selection of its election candidates and then mishandling revelations that one of its candidates uttered disgustingly sexist and derogatory slurs in the past, which critics said proved he was unfit to be a national legislator.

The remarks, which candidate Kim Yong-min, competing in a Seoul district, uttered during an Internet radio talk show in 2004, were so inflammatory they overshadowed opposition allegations that state authorities undertook extensive spying on civilians critical of the Lee administration.

The opposition party apologized but did not expel Kim or cancel his election nomination, apparently because he appealed to younger voters. Kim became popular as a co-host of an online talk show that is harshly critical of Lee and the ruling party.

Kim ended up losing his race on Wednesday.

Results also showed that regionalism weighed heavily in the elections. The ruling party dominated districts in its home turf of the southeastern Gyeongsang provinces, while the opposition party almost swept its home base of the southwestern Jeolla provinces.

In Seoul, the opposition DUP and its coalition partner won 32 seats against the ruling party's 16 seats. Many heavyweight politicians from the ruling party lost the races in Seoul, including former ruling party leader Hong Joon-pyo.

Hong, a four-term lawmaker, conceded defeat and announced his retirement from politics.

The final voter turnout was 54.3 percent, 8.2 percentage points higher than four years ago.

The outcome is expected to have little effect on major domestic and foreign policies of South Korea. There had been concern that the emergence of an opposition-controlled parliament could affect the free trade agreement with the United States. (Yonhap)