Supreme Court judges in Brazil began voting Wednesday on whether to overturn a law requiring convicted criminals to go to jail after losing their first appeal, instead of waiting until the end of the legal process.

A favorable ruling could result in the freeing of scores of convicts, including leftist former president Luiz Inacio Lula da Silva, who is serving eight years and 10 months for corruption.

The eleven justices are expected to finish voting Thursday, in a closely-watched decision that is being broadcast live.

Lula is among scores of high-profile political and business leaders caught up in the sprawling corruption probe known as "Operation Car Wash."

The popular leftist leader has been incarcerated at the federal police headquarters in the southern city of Curitiba since April 2018.

Lula was sentenced to almost 13 years in jail in February in a separate corruption case and still faces another half dozen corruption trials.

A supporter of Brazil's Workers Party holds a mask with the face of imprisoned former Brazilian president Luiz Inacio Lula da Silva
A supporter of Brazil's Workers Party holds a mask with the face of imprisoned former Brazilian president Luiz Inacio Lula da Silva AFP / DANIEL RAMALHO

He has denied all the charges, arguing they were politically motivated to prevent him from competing in the 2018 election, ultimately won by President Jair Bolsonaro.

If he is released, Lula's criminal record will prevent him from resuming his political career.

That could change, however, if the Supreme Court were to decide in a separate case that Justice Minister Sergio Moro, who convicted Lula when he was a judge in 2017, had been biased.

Moro, who joined Bolsonaro's cabinet in January, has faced calls for his resignation over leaked chats purportedly showing he worked with Car Wash prosecutors to keep Lula out of last year's presidential race.

Moro has denied any wrongdoing.

Under Brazilian law, Lula is eligible to apply for house arrest after serving one-sixth of his sentence.

He has so far refused to do so as he waits for the Supreme Court ruling on Moro, which could annul his conviction and result in a re-trial.