Updated

Prosecutors have argued in an Australian appeals court that child sex convictions against a Roman Catholic cardinal should not be overturned and say his accuser had been a compelling witness.

Cardinal George Pell is the most senior Catholic to be convicted of child sex abuse and is appealing those guilty verdicts in the Victoria state Court of Appeal.

Prosecutor Chris Boyce told the three judges on Thursday that the convictions largely based on the testimony of a single accuser should stand.

A jury unanimously convicted Pell in December of orally raping a 13-year-old choirboy and indecently dealing with the boy and the boy's 13-year-old friend in a Melbourne cathedral in the late 1990s.

One of the boys, now in his 30s, was the key prosecution witness in the case.