TAIPEI (AFP) - Supporters of Taiwan's former president Chen Shui Bian renewed calls Tuesday for the government immediately to parole him for medical treatment after Chen attempted suicide in prison.

Chen, who is serving a 20-year sentence for corruption, tried to hang himself with a towel in a bathroom of a prison hospital on Sunday night but was prevented by a guard.

Chen, who began serving his term in a Taipei jail in 2009, was transferred to the prison hospital in April after he was diagnosed with severe depression, a nerve disorder and other health conditions.

His family and supporters said the attempted suicide showed Chen's frail emotional state. They expressed anger that the 62-year-old was repeatedly denied medical parole even though doctors recommended home care for him.

"It is unacceptable for the government to ignore professional medical advice. We call for immediate parole for Chen for treatment," said Mr Lin Chun Hsien, spokesman for the opposition Democratic Progressive Party which Chen once led.

Rights groups also urged the government to examine some judicial problems raised by Chen's case, including what they see as the lack of transparency in reviewing medical parole requests.

"Currently it is the justice ministry's unilateral decision. There is a need to form an independent committee to make the process transparent and effective," said Mr Tsai Chi Hsun, secretary-general of the Taiwan Association for Human Rights.

The justice ministry has said home care is not an option for inmates, and Chen does not qualify for immediate parole on medical grounds because he can receive treatment in the prison hospital.

Chen said the suicide attempt was in protest at being excluded from an amnesty that last week saw charges dropped against hundreds of local politicians and academics accused of misusing government funds.

The justice ministry said Chen has been eating properly and receiving visitors from Monday and his emotional condition has stabilised.

Chen was convicted of corruption and money-laundering relating to his 2000-2008 presidency. He was sentenced to life in prison in 2009 but the term was later reduced after appeals.

Chen and his family were accused of laundering millions of dollars by sending political donations and secret diplomatic funds abroad, and of taking kickbacks on government contracts.

The ex-leader insists that the charges against him are part of a politically motivated vendetta by the current government in retaliation for his eight years in power when he promoted Taiwan's independence from China.