TAIPEI, July 31 (Reuters) - Taiwan prosecutors on Tuesday pressed additional charges against the island's main opposition presidential candidate, who is on trial for corruption, the state-funded Central News Agency said.

Ma Ying-jeou of the Nationalist Party, or Kuomintang, has pleaded not guilty to charges he misappropriated around T$11 million (US$335,000) over five years during his tenure as mayor of the capital Taipei from 1998 to 2006.

Taipei prosecutors pressed additional charges of breach of trust and fraud against Ma on Tuesday, recommending a prison sentence of seven years for each, the news agency said.

"I want to stress I did not commit any crime ... So far prosecutors have not provided sufficient evidence to prove that I committed any crime," Ma told reporters as he emerged from the 14-hour hearing greeted by flag-waving supporters.

It was not clear when the Taipei District Court would deliver its verdict.

Ma has said he will not withdraw his presidential bid if convicted.

He was known for his clean image and his indictment in February sparked opposition accusations of political persecution.

Media surveys show Ma ahead of Frank Hsieh, the candidate of the ruling Democratic Progressive Party (DPP), but analysts say the March 2008 elections are highly unpredictable.

Ma favours closer economic ties with China. The DPP advocates formal independence for self-ruled Taiwan, which Beijing claims as its own, but Hsieh is himself a moderate.