Patek was found to have made the bombs used in the assault on Bali, a Hindu island popular with foreign tourists.
He was captured with a $1 million bounty on his head after nearly a decade on the run.
Prosecutors only sought a life sentence for the 52-year-old on a charge of premeditated murder because he showed remorse during his 2012 trial.
Any release from prison must be approved by Indonesia's Ministry of Justice.
For survivors of the attack the thought of him leaving prison and living a normal life is difficult to bear.
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"Deep down in my heart, I cannot accept it but I am trying to," said Chusnul Chotimah, another survivor who suffered severe burns that have left scars across her face and body.
Australia has also been angered by the news of Patek's sentence reduction.
The country lost 88 of its citizens in the attacks, the most of any of the 21 countries whose nationals were killed.
Albanese said he had nothing but "contempt" and disgust for Patek's actions, saying his early release would only renew distress and trauma for the victims' grieving families.
But Chotimah met with Patek's relatives and said she learned they had also suffered from the tragedy he helped to commit.
The 52-year-old is trying to make peace with what happened to her, despite the news of Patek's potential release before the anniversary of the day that changed her life.
"The longer I keep the grudge, the more aching my heart is," she said.
Source: Agence France-Presse
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