TAIPEI (AFP) - Taiwan's President Ma Ying-jeou apologised on Friday after one of his confidants was implicated in a corruption scandal, just months after another friend resigned from the cabinet amid bribery accusations.

Lai Su-ju, a member of the Taipei City Council, was interrogated and released on bail early on Friday on suspicion of soliciting and accepting money from a company in a massive construction project in the capital, prosecutors said.

"I am shocked and saddened that Lai Su-ju, a partner of our team for a long time, is involved in a legal case ... I apologise to all party members and to the public," said Mr Ma, who is also chairman of the ruling Kuomintang (KMT) party.

Mr Ma said in the statement that he respected and supported the investigation while urging Lai to "bravely face the judiciary to clarify the case and reveal the truth".

Lai solicited NT$10 million (S$420,000) to help facilitate the NT$70 billion project, the United Daily News reported, although prosecutors declined to give specifics. She maintains her innocence.

Lai, 49, was a rising star in the KMT and formally served as the party's spokeswoman. As a lawyer, she has represented the president and other top politicians in several high-profile court cases.

She became the second KMT politician with close links to the president to be implicated in corruption scandals since October, when former party vice chairman and cabinet secretary-general Lin Yi-shih was indicted on graft charges.

Lin, also seen as a confidant of Ma, resigned from the cabinet after he was accused of taking bribes from a businessman to help him obtain contracts with a state firm.

Observers said Lin's case dealt a heavy blow to Mr Ma, who was re-elected for a second and final four-year term last year pledging to fight corruption.

Taiwan has been rocked by a string of corruption cases involving top officials in recent years, including ex-president Chen Shui-bian who is currently serving a 20-year jail term on multiple graft convictions.