South Korea's ruling party secured a surprise win in parliamentary by-elections on Wednesday.

They took more than half of the seats up for grabs.

Lee's Grand National Party won five of the eight National Assembly seats in the electoral contest. One of the president's closest political advisors, Lee Jae-oh, won his seat handsomely, defeating a high profile rival close to the deceased former South Korean President Kim Dae-jung.

The win will boost the political standing of President Lee Myung-bak.

The president had been fighting speculation his rule was entering a "lame duck" period.

[Kim Hyung-joon, Professor, Myongji University]:
"The by-elections will delay lame duck status for President Lee for a while and the result gave him an opportunity to run the state affairs with confidence."

Voters say they selected their candidates for a variety of reasons.

[Kang Ki-soo, Voter]:
"I voted based on assessment of each candidate rather than the candidates' parties. Our village people at the markets talked about which candidate could work for us. So I voted for the person who could work best for us."

[Han Kwang-woo, Voter]:
"I voted based on assessment of political parties. I selected a candidate from a party which has better sense of national security amid the North-South Korean confrontation."

Last month Lee's party suffered defeats in traditional strongholds during local elections. That prompted speculation the president will be politically crippled as he enters the second-half of his five year term.

Traditionally, South Korean presidents in their latter years are weakened by scandal and political maneuverings.

But President Lee has been trying to present himself as being in tune with the concerns of the middle class.