Muhammad Ali said his client was detained for alleged involvement with a new militant network in Indonesia's westernmost province of Aceh.
Bashir is best known as the spiritual leader of Jemaah Islamiah, the al Qaida-linked terrorist group responsible for the 2002 Bali bombings that killed 202 people.
He spent several years in prison for his involvement with the group, but was released in 2006.
Mr Ali said Monday's arrest took place in West Java's Ciamis district.
COMMENT RULES: Comments that are judged to be defamatory, abusive or in bad taste are not acceptable and contributors who consistently fall below certain criteria will be permanently blacklisted. The moderator will not enter into debate with individual contributors and the moderator’s decision is final. It is Belfast Telegraph policy to close comments on court cases, tribunals and active legal investigations. We may also close comments on articles which are being targeted for abuse. Problems with commenting? email@example.com