SYDNEY - A Brazilian drug trafficker executed in Indonesia, who was diagnosed with schizophrenia and bipolar disorder, did not understand what was happening to him until his final moments, a priest assigned as his spiritual adviser told Australia's ABC radio on Thursday.

Rodrigo Muxfeldt Gularte was among eight drug convicts from several countries who were executed shortly after midnight on Wednesday morning, Reuters reported.

Brazil had made repeated personal pleas for Indonesia to commute his sentence on humanitarian grounds, citing his mental illness, said the report.

Father Charlie Burrows, a local priest who accompanied Gularte in his final hours, told ABC he thought he had prepared the Brazilian for the execution. "I thought I'd got him ready, that he was going to be put in chains, because he didn't like being touched ... I said to him, well I'm 72, when you get up to heaven you'll know where I'm going to live, prepare a garden or something," Burrows said.

Gularte was calm as he was handcuffed by warders but became agitated when he was handed over to police outside the jail who put leg chains on him, Burrows said.

"I thought he'd got the message he was to be executed but ... when the chains started to go on, he said to me, 'Oh father, am I being executed?'," Burrows said.

Burrows, who witnessed the execution of another Brazilian prisoner in January, said Gularte continued to hear voices in his final days, telling him everything would be fine. "He believes the voices more than he does anybody else," he said.

Gularte was caught entering Indonesia in 2004 with 6kg of cocaine hidden in surf boards, and was sentenced to death in 2005, according to Reuters.

The 42-year-old's family presented several doctors' reports to the Indonesian authorities attesting to his mental illness, and Brazilian President Dilma Rousseff had made personal pleas on his behalf. Rousseff recalled Brazil's ambassador to Jakarta after the first execution in January.

On Wednesday, Australia also withdrew its ambassador from Indonesia in protest against the execution of two Australians - Andrew Chan and Myuran Sukumaran - ringleaders of the "Bali Nine" heroin trafficking gang,

The rest in the group who were executed early Wednesday morning were four Africans and one Indonesian.

When asked about the implications for Indonesia, President Joko Widodo said "this is our legal sovereignty". He appealed to Australia to respect Indonesia's legal sovereignty as his country respects theirs.

Mr Joko, who came to power last October, has pledged tough measures against drug abuse, including no clemency for convicted traffickers on death row.

He cited dramatic estimated figures as a basis for his tough measures, saying about 50 people die of drug use each day in Indonesia.