Radical Indonesian Islamic cleric Abu Bakar Bashir, convicted of funding terrorism, lodged an appeal for acquittal Tuesday after his jail term was slashed last month, his lawyer said.

The 73-year-old Bashir, who is regarded as a spiritual leader of militant Islam in Indonesia and is an outspoken supporter of Al-Qaeda-style jihad, had his jail sentence slashed last month from 15 years to nine.

"We lodged an appeal at the cassation (supreme) court," lawyer Achmad Michdan told reporters after registering the appeal.

A lower court in June sentenced Bashir to 15 years in prison for deliberately inciting terrorism and funding a new terror cell in Aceh province, allegedly planning deadly attacks on Westerners and politicians.

"We are convinced that the cleric was never involved in the Aceh" affair, Michdan said.

The Jakarta High Court ruled last month that Bashir had been involved in a less serious offence, and because of his advanced age his sentence should be reduced.

Michdan said that in the appeal, the team of lawyers questioned testimony given by several key witnesses via Internet videophone.

"They prepared it secretly without our knowledge. That was a violation of judicial procedures," he said.

The bespectacled cleric served almost 26 months behind bars for conspiracy over the 2002 Bali bombings that killed 202 mainly Western tourists, including 88 Australians.

But that conviction was overturned in the Supreme Court after his release in 2006 and other allegations of terrorism -- including suspected roles in deadly bombings in 2000 and 2003 -- have never been upheld in court.

He was jailed again in June.

Indonesia has been rocked by a series of attacks staged by the regional terror network Jemaah Islamiyah in recent years.

"I hope that with this appeal, our cleric will be freed," Michdan said.