The first sexual offence complaint against Cardinal George Pell set off a "domino effect" of allegations but should not be believed, a court has been told.
The initial complaint came from an "unreliable and uncredible" source, Pell's legal team told the Melbourne Magistrates Court during an administrative hearing regarding documents on Wednesday.
Defence barrister Ruth Shann said the first allegation to police came via a royal commission in 2015, 40 years after the alleged acts.
Ms Shann said newspaper coverage of the royal commission prompted the complainant to come forward.
"We will be saying that that complaint and the basis for it lacks reliability and credibility," she told the court.
Ms Shann said the initial complaint set off a chain of events of others making allegations against Pell, noting it was the first time they made a complaint to anyone at all.
"The domino effect which occurred with those other people starts from an unreliable and uncredible source," she said.
The court was told Pell's lawyers will challenge that first step, arguing it was flawed and not to be believed.
The comments were made during an administrative mention of Pell's case, before a March hearing to determine if he stands trial on historical sexual offence charges involving multiple complainants.
Magistrate Belinda Wallington denied the defence access to the complainants' medical records.
A further mention will be held next Wednesday to finalise matters before the March 5 hearing.
Pell, the highest-ranking Catholic official to be charged with sexual abuse, denies the charges.
The 76-year-old was not in court on Wednesday.
The former Sydney and Melbourne archbishop and Ballarat priest has taken leave from his position as Vatican treasurer to fight the charges.