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An Australian court will decide on Wednesday whether Cardinal George Pell is permitted to challenge his conviction for child sexual abuse.

Pell was found guilty by a jury last year of abusing two boys inside a Melbourne cathedral in 1996. He was later jailed for six years.

The ex-Vatican treasurer, 77, is the most senior Catholic figure to be convicted of such crimes.

He maintains his innocence and argues the verdict was unreasonable.

If a court in Melbourne allows his appeal to proceed, it will immediately take place over two days of hearings.

Pell's conviction has rocked the Catholic Church, where the Australian cleric was considered one of Pope Francis's closest advisers.

What was Pell convicted of?

Last year, the County Court of Victoria heard that Pell had abused two 13-year-old boys following a mass in 1996, when he was archbishop of Melbourne.

A jury unanimously convicted him on one charge of sexually penetrating a child under 16, and four counts of committing an indecent act on a child under 16.

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The trial heard testimony from one of the victims. The other died of a drug overdose in 2014.

Pell chose not to give evidence during the trial.

How is he arguing for an appeal?

Pell wants to contest the verdict on three grounds. The first asserts that it was "unreasonable" because it relied too heavily on the testimony of the surviving victim.

The jury had also heard "unchallenged" evidence from 20 other prosecution witnesses, they argue.

The second aspect of the appeal asserts that the trial judge had wrongly prevented a defence animation from being played at the trial.

The video represents the locations of witnesses inside St Patrick's Cathedral. Pell's lawyers argue that he could not have committed abuse because it was impossible for him to be alone.

The third challenge contends that Pell was prevented from entering his plea before a jury - against court process.

What could unfold?

The hearing on Wednesday will be heard by three judges in the Court of Appeal - a division of the Supreme Court of Victoria.

The appeal will be heard immediately - and conclude on Thursday - if the court allows it to proceed.

In that scenario, it will be up to the judges to determine whether the jury could have been satisfied that Pell was guilty beyond reasonable doubt. A decision requires only two of the three judges to agree.

A successful appeal could result in a retrial or Pell being immediately released, legal experts say.

If the appeal is heard, when would a decision be known?

Experts say it could happen either immediately after the hearings, or the judges could reserve their ruling for a later date.

What's been the reaction previously?

Pell's surviving victim - who cannot be named - has previously expressed concern that the verdict could be overturned.

"There is no rest for me. Everything is overshadowed by the forthcoming appeal," he said in March.

The Vatican said they found the conviction to be "painful news", but also that Pell had a right to "defend himself to the last degree".

The cleric was removed from the Pope's inner circle in December, and his term as Vatican treasurer expired earlier this year.