South Korean voters went to the polls Thursday in parliamentary by-elections viewed as a bellwether for December's presidential race. The opposition Grand National Party is expected to triumph.

Thirteen seats and control of the 273-member National Assembly are being contested Thursday in South Korea. Political analysts forecast a repeat of June's local elections with a landslide victory for the opposition because of low turnout and regional rivalries among South Korean provinces.

Several hours before voting booths closed, an independent election committee estimated that less than 23 percent of eligible voters cast ballots. The election comes in the midst of summer holidays. Torrential rains in some parts of the country also discouraged voters from visiting polling stations.

Political analysts say the main reason for low turnout is public dissatisfaction with politicians, who many people consider to be corrupt.

Newspaper editorials complained Thursday of a dearth of policy debate within the assembly or on the campaign trail.

South Korean President Kim Dae-jung has appealed for a fair and orderly election, but his reputation has been damaged by corruption scandals involving two of his sons.

Mr. Kim has apologized to the public for his sons' problems and in May resigned from the Millennium Democratic Party, which he founded.

Some political analysts predict that a poor showing Thursday by the MDP could contribute to its break-up.

Voters will choose a new president on December 19. The incumbent is by law barred from seeking another term.