Any allegation of misconduct levelled at Cardinal George Pell while he was in the sacristy at a cathedral could not possibly have happened, a Melbourne court has been told.

Catholic priest Charles Portelli gave evidence to Cardinal Pell's committal hearing as he fights historical sexual offence charges involving multiple complainants.

No other details of the charges can be reported for legal reasons.

Father Portelli assisted the 76-year-old during cathedral ceremonies and told the hearing Cardinal Pell was never alone, before, after or during those masses.

He told the hearing he would help Cardinal Pell put on and take off his robes for masses in the sacristy.

Defence barrister Robert Richter QC asked Father Portelli if it would have been possible for someone apart from other clergy or their assistants to have been in the sacristy when the archbishop was also inside with his robes on.

"No," he responded.

Father Portelli said it was "absolutely" impossible any allegation of misconduct levelled at Cardinal Pell while he had his vestment on in the sacristy could be true, as he was never alone there while robed.

He said he would normally leave the cathedral with Cardinal Pell after mass so he could drive him to any afternoon engagements.

But Father Portelli told the court there had been instances when Cardinal Pell did not have any post-mass commitments and would leave alone.

New statement raises possibility of further charges

Earlier, the court was told one of the witnesses due to be called at the committal hearing had unexpectedly provided a new statement to police on Monday.

His first statement had placed Cardinal Pell at the location where some of his offending is alleged to have occurred, the court was told.

Mr Richter said the man's latest statement had raised questions about whether further charges would be laid and asked for him to be removed from the police brief of evidence.

The man will no longer give evidence during the current hearing.

Their evidence cannot be reported.

It is expected to be another two weeks before the hearing concludes and Magistrate Belinda Wallington rules on whether there is enough evidence to commit Cardinal Pell to stand trial.

Editor's note: On Tuesday April 7, 2020, the High Court in a unanimous decision upheld Cardinal Pell's appeal and quashed his convictions on all five charges.