Indonesia will release radical cleric and alleged mastermind of the 2002 Bali bombings Abu Bakar Bashir from prison later this week, upon completion of his jail term.
Bashir, 82, who was among Indonesia's most notorious extremists, is considered by some to be the spiritual leader of the Jemaah Islamiah network.
He was jailed in 2011 for his links to militant training camps in Aceh province.
Bashir will be released on Friday "in accordance with the expiration date and the end of his term," Rika Aprianti, spokeswoman of the corrections directorate general at the law and human rights ministry, said in a statement.
Federal cabinet minister Angus Taylor said while it's a matter for the Indonesian government it was understandable Australians would be feeling distressed.
"This is distressing for many of those families that have been affected by those tragic events some years ago," he said in Goulburn on Tuesday.
"We have expressed our concern about the situation and will continue to, but I do feel for those families because it does bring back those extraordinary events that we all remember so well and the tragedy that unfolded."
Foreign Minister Marise Payne said the Australian embassy in Jakarta had made clear Australia's concerns that those responsible for bombings in 2002 and 2005 be stopped from inciting others to carry out attacks.
She said Australian law enforcement and security agencies had confidence in Indonesia's counter-terrorism capabilities, but she understood the news would be distressing for families and friends of the Australians who had died or been injured.
JI is accused of plotting several big attacks in Indonesia and includes operatives trained in Afghanistan, Pakistan and the southern Philippines.
Its members are accused of orchestrating the 2002 bombings of Bali nightclubs, which killed more than 200 people, among them scores of Australians, and an attack on the JW Marriott hotel in Jakarta that killed 12 people a year later.
A senior JI operative believed to have made bombs for both attacks, Zulkarnaen, was among 23 suspected militants arrested last month.
Bashir denied any involvement in the Bali bombings.
Security analyst Ridlwan Habib said that though Bashir's stature has weakened, extremists may try to associate their activities with him to gain traction and boost their credibility.
While seeking re-election, President Joko Widodo in January 2019 had considered an early release for Bashir on health grounds but scrapped the plan after Bashir reportedly declined to pledge allegiance to the Indonesian state ideology.