Prosecutors in South Korea have indicted the brother of the opposition leader Lee Hoi-chang on charges of raising illegal political funds for him during last year's presidential campaign.

Lee Hoi-sung was accused of collecting more than twelve million dollars for his brother, who was then the presidential candidate for the ruling party.

Prosecutors said Lee Hoi-sung colluded with senior tax officials to pressure at least twenty large businesses to contribute funds to his brother's campaign.

The opposition leader and his brother have denied any involvement in the scheme.