The Tainan branch of the Taiwan High Court upheld a lower court's verdict that Chang's election victory in January 2008 was not fair and invalid because of vote-buying scams.

Chang had claimed that he was unaware of his father's scheme to buy votes for him in the election. But the High Court found that the lawmaker's argument for innocence was not convincing.

The ruling is final, and a by-election has to be held in the Yunlin County district within three months in accordance with the law.

The court's decision will not affect the ruling KMT's grip of the parliament because of the large majority it maintains.

Chang won a regional legislative seat in Yunlin County's second district in January last year, but his defeated opponent, Liu Chien-kuo of the opposition Democratic Progressive Party (DPP), accused Chang of vote buying and filed a lawsuit seeking to invalidate his election.

The Yunlin District Court granted Liu's request Nov. 28, 2008 on the ground that Chang Sho-wen was believed to be aware of and had taken part in a well-planned and well-organized vote buying scheme masterminded by his father Chang Hui-yuan, president of an influential local agricultural irrigation association.

The elder Chang had already been sentenced to five years and eight months in jail in a separate case for colluding with the irrigation association's staff members and grassroots neighborhood chiefs in the county to canvas support for his son by offering cash to voters.

The senior Chang denied the charges and also appealed his sentence. But the imprisonment plus a fine of NT$2 million were also held up by the high court yesterday.

Legislator Chang Sho-wen expressed his regrets that the judicial system failed to deliver a just ruling he had expected.

But he vowed to have a fresh start for his political career in order to serve his supporters.

Liu Chien-kuo who initiated the suit against Chang Sho-wen said that he will definitely compete in the by-election on behalf of the DPP.

Chang Sho-wen is the second incumbent lawmaker who had his election annulled by the court for vote-buying after a general election early last year.

Lee Yi-ting, also a KMT lawmaker, from Miaoli County was stripped of his legislative seat after his appeal against a district court's decision to invalidate his election was rejected on Dec. 10, 2008.

An independent candidate who broke away from the KMT was elected to replace him in a by-election in March this year.