By Charles Scanlon
BBC correspondent in Seoul
After months of political feuding that culminated in the impeachment of President Roh Moo-hyun, the South Korean people have given their verdict.
South Koreans were largely opposed to the president's impeachment
They have handed a clear victory to the president's loyalists in the liberal Uri party.
The ruling camp looks set to win a majority in the National Assembly - more than tripling its seats.
"The people have protected democracy, the people have protected the president," said the chairman of the Uri party Chung Dong-young.
"This election means that the old political forces that have dominated South Korean politics for 44 years are forced to leave the stage."
Analysts see the result as a vote for stability.
President Roh's approval rating had slumped to 30% last year after a halting and inconsistent start to his five year term.
But the mood changed last month when the head of state was impeached by his conservative opponents on seemingly trivial charges.
He was accused of corruption and illegal campaigning for speaking out in favour of the Uri party.
"The impeachment was against the will of the majority and wasn't just. I used to support the opposition but no more," said young mother Suh Jin-hee.
The Uri party counted on the support of young voters in their twenties and thirties who are overwhelmingly hostile to the conservative establishment.
The conservative Grand National Party has been damaged by a massive political funding scandal in recent months.
It was found to have taken tens of millions of dollars in black money from big business.
"The majority think if you stay in politics for a long time, if you're old you're corrupt," says Professor Hahm Seung-deuk of Korea University.
"President Roh presents himself as an outsider who can clean up politics, that's why he's very attractive to voters."
Already in a weak position the GNP shot itself in the foot by forcing through the impeachment of the president.
There were scuffles and brawls in the National Assembly - scenes that appalled a public already disillusioned with politicians.
MPs tried to physically prevent the impeachment vote being called
This election has seen the emergence of many fresh faces. More women and younger candidates have come forward - people untainted by the discredited money politics of the past.
The conservative opposition, however, did stave off disaster at the polls.
It managed to shore up support in its south-eastern stronghold - an indication that long established regional divisions are still strong.
President Roh must now wait for the final verdict on his impeachment from the constitutional court. If he is cleared of the charges against him he will be returned to office in a much stronger position.
The Constitutional Court is supposed to make a legal ruling. But analysts speculate it could be influenced by the public mood.
The victory of the centre-left has consolidated a pronounced left-ward drift in South Korean politics.
Many of the president's supporters are sceptical of the alliance with the United States and are sympathetic to the plight of North Korea.
President Roh adopted pragmatic middle of the road policies during his first year in office.
He says he is committed to the free market and the alliance with Washington.
But if he is returned to office with a parliamentary majority - conservatives fear he will be less constrained in his policies.