Umar Patek, a convicted terrorist and the main bombmaker in the 2002 Bali bombings, has been released from jail in Java in a move the Australian Home Affairs Minister has described as a "horrible day for victims".
Patek helped build the car bomb that killed more than 200 people in the nightclub attacks, including 88 Australians, and served just over half of his original 20-year sentence.
Australia had lobbied hard to have him kept in jail for his full term, with Prime Minister Anthony Albanese in August describing his imminent release as "abhorrent".
But Indonesian authorities say he has fulfilled all the requirements for parole, after earning remissions for good behaviour.
"The special requirements that have been met by Umar Patek are that he has participated in the de-radicalisation coaching program," Ministry of Law and Human Rights spokesperson Rika Aprianti said at a press conference on Wednesday.
She told the ABC Patek "must report to the parole office" at first for once a week, "and after that it would be once a month".
He will remain on parole until 2030 but it can be revoked if he fails to report or breaks the law.
Patek 55, whose real name is Hisyam bin Alizein, was a leading member of the Al Qaeda-linked network Jemaah Islamiyah, which is blamed for the bombings at two nightclubs in Kuta Beach.
He received a total of 33 months of sentence reductions, which are often given to prisoners on major holidays, Ms Aprianti said.
Most recently, he was granted a five-month reduction on August 17, Indonesia's Independence Day.
That meant he had fulfilled the parole requirement of serving two-thirds of his current sentence, she said.
Patek was found guilty by the West Jakarta District Court of helping build a car bomb that was detonated by another person outside the Sari Club in Kuta, moments after a smaller bomb in a backpack was detonated by a suicide bomber inside the nearby Paddy's nightclub.
Patek was sentenced to 20 years in prison a decade after the bombing.
He left Bali just before the attacks and spent nine years on the run, during which he was considered one of Asia's most wanted terror suspects.
Victims have 'deepest sympathy of the Australian government'
Home Affairs Minister Clare O'Neil described Patek's release as an "absolutely horrible day for the victims of the Bali Bombings".
"I think all Australians should be thinking today of those families [who lost loved ones]," she said at the National Press Club.
"It was a complete tragedy what happened in Bali, one of our worst terrorist incidents in Australian history."
Ms O'Neil said victims' families have the "deepest sympathy of the Australian government today".
"My personal view is [the] actions are inexcusable and completely abhorrent," she said.
Ms O'Neil also said the Australian government "has put in the strongest possible terms our views about what has occurred, and we have done that clearly".
Survivors says de-radicalisation 'fanciful'
Simon Quayle was at the Sari Club with his football team on the night of the attack and has reflected on Patek's release.
He says he trusts Indonesia's justice system, considering how quickly they acted after the bombings.
"It may not be the common opinion of everyone, but I don't actually have any bitter feelings or hatred or revenge relating to the release of this individual," he told ABC Radio Perth.
"I reflect on their justice system to say how quickly they were able to capture and execute or put in jail those people responsible for the Bali bombings, and that made me feel really safe."
Mr Quayle said Patek's release is part of the healing process and moving on from the tragedy.
"He's reformed, the Indonesian government have said," he said.
"Their system held up really well in regard to the justice originally so and I think it's a good thing for me personally, and all of us just to move a little bit further away from that defining moment."
Bali bombing survivor Peter Hughes said he was not surprised by Patek's release and called claims of his de-radicalisation "fanciful".
"There's no chance of him actually being turned around," Mr Hughes told the ABC.
"How could he be [de-radicalised]?
"This guy was a mastermind that set this all up along with people like [Abu Bakar] Bashir and many others.
"And there's a history of people like him. They won't stop.
"For him to be let out, it's laughable."
"I remember going to Jakarta and we were going into that courtroom and sitting down and waiting for this person to walk in," he said.
"And he was somebody that was less than five-foot tall."
He said the group of Australians were looking for Patek to receive a longer sentence than what he received, a sentence that had now been cut almost in half.
"[We were] determined to make sure this guy got the harshest sentence ever. And he didn't get that," he said.
Mr Hughes said he hoped the Australian government would take a strong stance in its response to news of Patek's early release.
"I think they should step forward and say to the Indonesian president that this isn't good enough, and I think they need to put their foot down," he said.
"We can't change what the Indonesian government want to do their own people, but at least we could actually say something.
"I wouldn't like it to be passive. I'd like it to be fairly heavy handed."
