In 11 of the 42 cases, law enforcement officers allegedly intimidated or tortured the defendants or witnesses, according to the report by the Institute for Criminal Justice Reform.

Defendants in 11 cases also did not appear to have had proper access to legal assistance.

Bali nine organisers Myuran Sukumaran and Andrew Chan are among 10 drug felons who are facing the firing squad in the second round of executions to be held in Indonesia this year.

Many of those on death row with the Australians claim they did not receive a fair trial, including impoverished Indonesian labourer Zainal Abidin, French welder Serge Atlaoui and Filipina domestic helper Mary Jane Fiesta Veloso.

The report said that a lawyer was only present in Zainal Abidin's case after his interrogation had taken place.

Capital punishment is the heaviest sentence an Indonesian court can impose and therefore should be reserved for the most serious criminals and the ringleaders of crime syndicates, the report said. However "in practice", defendants with a minimal role who were not even involved in the planning of a crime were often given the death penalty.

The report pointed to Bali nine mule Scott Rush, who was sentenced to death by the Bali High Court in 2006. It was only during his appeal that the Supreme Court took into account that Rush was merely a courier and commuted his sentence to life imprisonment.

The Institute for Criminal Justice Reform review was prompted by the case of Yusman Telaumbanua, who was apparently only 16 when he was found guilty of murdering three gecko sellers in 2012.

Women's Empowerment and Child Protection Minister Yohana Yembise called for a review of his sentence in March, amid allegations he was tortured during questioning at the Nias Police station three years ago and was a minor when found guilty.

The Institute decided to review decisions made in the District, High and Supreme courts to see if the principle of a fair trial was being applied in Indonesia's criminal justice system. The report found repeated problems including lack of access to legal aid, lack of proof from the prosecution, and inconsistencies in judges' rulings.

The Institute urged the government to review all court decisions that imposed the death penalty. It also called for a moratorium on executions and the imposition of the death penalty until defendants could be assured of a fair trial.

Meanwhile Atlaoui, the Frenchman who is facing the firing squad with Chan and Sukumaran, had his appeal thrown out of the Administrative Court last week on the grounds that the court did not have the jurisdiction to challenge a presidential decree.

Lawyer Nancy Yuliana said she would appeal the ruling in the same court within two weeks.

Chan and Sukumaran lost a similar appeal last Monday.

Ms Yuliana said she understood that the rejection of clemency pleas was the final legal avenue but this should not be the case when the defendant felt there had been a miscarriage of justice. "Our client has the right to defend his life although it may have the same result [as the Bali Nine duo's case]," Ms Yuliana said.

Atlaoui was arrested at a methamphetamine laboratory in Tangerang in 2005. He has always maintained his innocence, saying he was merely a welder installing equipment in what he thought was an acrylics factory.

"He is not a chemist who understands chemical substances," Ms Yuliana said. "Moreover Serge is only a mechanic, he is not the owner, but he is sentenced to death just like the drug factory owner."

Nine people arrested with Atlaoui have also been sentenced to death, however Ms Yuliana said Atlaoui was the first to face the firing squad even though "we all know that people from the same case must be executed together".

"Why is it only our client that is singled out to be executed?" she asked. "It is absolutely unjust."

with Karuni Rompies