Myuran Sukumaran was shot dead by firing squad late last month after his pleas for clemency over his role in a syndicate smuggling heroin from the Indonesian island of Bali were rejected.

Ben Quilty, an acclaimed Australian artist who became a friend and mentor to Sukumaran through visiting him in jail, said the 34-year-old did not want to die but had done so with dignity.

"He used his visual language to tell the world who Myuran Sukumaran really was and right until the end he communicated with the world from an isolation cell with a firing squad preparing to put bullets through his chest," Quilty said.

"Under unimaginable circumstances Myuran was making the most potent and powerful anti-death penalty images the world has seen in a long, long time.

"Myu did want to live. He had many paintings to make."

Sukumaran and fellow Australian Andrew Chan, considered the ringleaders of the so-called Bali Nine drug smuggling group, spent a decade in prison before their execution on April 29.

A funeral for Chan, 31, was held in Sydney on Friday.

Both men were transformed by their experience in jail with Chan becoming a Christian pastor and Sukumaran studying art.

Songs sung at Sukumaran's funeral at the DaySpring Church in Sydney's Castle Hill included "Amazing Grace" which he and his fellow prisoners sang ahead of their execution.

"Until the end, under very difficult circumstances, in prison for 10 years, he was helping and comforting all others in Kerobokan prison in Bali," Ivar Schou, a volunteer at the jail, told the mourners.

They heard that on one occasion, Sukumaran had sold his paintings to pay for another inmate's life-saving operation while fellow Bali Nine member Matthew Norman said he had helped countless prisoners, including drug addicts and murderers.

Mother Rajini Sukumaran said her son died a good man, in a tribute delivered by son Chinthu after she was overcome by grief.

"He got caught up with something bad, and the anger and shame I felt when he was arrested, was gone a long time ago," she wrote.

Australia strongly opposes the death penalty and withdrew its ambassador to Indonesia for talks after Jakarta executed Chan and Sukumaran, along with five other foreigners and an Indonesian. (++++)

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