Singapore – Indonesia can do more to curb Islamic schools that served as a training ground for extremists who carried out some of the deadliest attacks since the September 11, 2001 strikes, a senior politician said on Monday.

Amien Rais, speaker of Indonesia's parliament, also told the World Economic Forum in Singapore that boosting intelligence services and cutting off the flow of illicit funds to groups intent on terror attacks were essential for security and to prevent Islam appearing in an unfavourable light.

Rais, former head of Indonesia's second-largest Islamic group, the 28-million-strong Muhammadiyah, said it was time to take another look at education in Indonesia and at the Islamic madrassah schools that have served as fertile ground for recruiting young men to terror networks.

"The government seems a bit hesitant to pinpoint schools as cells of spreading terrorism," he said, adding that the government of secular Indonesia could be afraid that a crackdown would result in a violent backlash.

Few analysts expect the government to do anything about the schools, especially before presidential elections next year when no politician wants to risk being branded un-Islamic in a nation which has the world's highest number of Muslims.

In Indonesia's East Java province, one school – Al-Islam – has come under the spotlight because of its links to three brothers arrested for the Bali bomb attacks on October 12 last year. A Bali court has sentenced two of the brothers to death and the third to life in jail for their role in the bombings, which killed 202 people.

Indonesia has blamed the Southeast Asian militant Muslim group Jemaah Islamiah for the Bali blasts. Some security experts say the group is Osama bin Laden's Southeast Asian wing.

Rais also mentioned Abu Bakar Bashir, the jailed cleric whom many Jemaah Islamiah members around the region have recognised as their leader but whom a court this year ruled as not being connected to JI.

"I don't know what to say ... I don't have solid proof," said Rais of the verdict. "From my logic, for sure, networks of terrorist groups are connected collectively or individually to Jemaah Islamiah (JI)."

The most famous Islamic school in Indonesia was al-Mukmin, said an August report by the Brussels-based International Crisis Group. It said the school was co-founded in the central Java city of Solo by Bashir.