South Korea's governing Millennium Democratic Party has said it will dissolve itself and launch a new party to try to shed its poor image.

The party suffered crushing defeats in a series of by-elections on Thursday when its opponents won control of the National Assembly.

The MDP, founded by President Kim Dae-jung just two-and-a-half years ago, has been damaged by a series of corruption scandals surrounding the president's key aides and two of his three sons.

Chang Dae-whan is the president's latest choice for prime minister

Separately, President Kim put forward the head of South Korea's largest business newspaper, Chang Dae-whan, as his new nominee for prime minister.

His original choice, Chang Sang, would have been the first woman to hold the largely ceremonial post, but her appointment was vetoed in parliament.

The main opposition Grand National Party now has overall control of that single-chamber National Assembly after Thursday's by-elections wins.

Political upheaval

The BBC's correspondent in Seoul, Caroline Gluck, says major changes are now under way in South Korea's political arena.

She says the MDP wants to make a fresh start to regain public confidence.

The move comes ahead of December's presidential elections to find the successor to Mr Kim, who may not stand again under constitutional rules.

The GNP candidate, Lee Hoi-chang, is the current front-runner.

His party expressed strong reservations about the new nominee for prime minister, who assumes the president's duties if he becomes incapacitated or dies.

Confirmation uncertain

The National Assembly could yet veto the appointment of Mr Chang, 50, who is the chief executive of the Maeil Business Newspaper.

A GNP spokesman, Nam Kyong-phil, said: "President Kim Dae-jung went against the opinion of the opposition party and the people by appointing Mr Chang acting prime minister."

He added: "As we are not able to form an opinion about the nominee's suitability for the post at this stage, we will do our best to determine if he is the right man for the job through parliamentary hearings".

The MDP welcomed the new man.

Party spokesman Lee Nak-yon said: "The new nominee seems to be a man of outstanding ability who has his own views on international affairs and the economy."