Natalie O'Brien – The scheduled release this week of Abu Bakar Bashir, alleged spiritual leader of the extremist group Jemaah Islamiah, could spark a fresh round of terror strikes.

Rohan Gunaratna, head of the International Centre for Terrorism and Political Violence Research, said the early release of Bashir on Wednesday would send a dangerous message to terror groups.

"Bashir is also the leader of the Majelis Mujahedin Indonesia... umbrella organisation of jihad groups in Indonesia," Dr Gunaratna said.

"He will mobilise them, he will politicise them. He has the credentials because he went to prison and he suffered. So people will join him, people will work with him. That's why he must stay in prison forever."

Bashir was sentenced to 30 months in jail for his part in the conspiracy surrounding the 2002 Bali bombing, which killed 202 people, including 88 Australians. He insists he is innocent and denies the existence of JI.

The al-Qa'ida-linked group has also been blamed for a string of bombings, including those at the Australian embassy and Marriott hotel in Jakarta.

JI was spawned by the militant group Darul Islam, which was the first organisation to seek the creation of an Islamic state in Indonesia in the 1950s.

Foreign Minister Alexander Downer said last week there was nothing the Australian Government could do about Bashir's release. "He will no doubt go back to whatever private activities he wants to undertake," he said. "But the Indonesian Government no doubt will be as keen as we are in making sure he doesn't go back into activities that aid and abet terrorism."

While JI expert Sidney Jones agreed Bashir's imprisonment had probably increased his support base because he could be seen as a symbol of defiance against the West, she was not convinced his release would be a major security threat. "In some ways, the organisation has moved on and there are factions that don't look to Abu Bakar Bashir for leadership, such as the group around Noordin Mohammad Top (the JI mastermind of the Bali bombings)," Ms Jones told ABC radio.

JI has been quiet in recent months, largely because of a string of raids by the Indonesian police counter-terrorism force, Special Detachment 88.