John Robert Whittaker - who worked at Bellambi's Holy Spirit College - remains behind bars after he was denied bail in Wollongong Local Court this week.

Whittaker, from Figtree, was arrested on Monday and charged with 11 offences - including aggravated indecent assault of a person aged under 16, committing an act of indecency with a person under 16 and aggravated sexual assault of a person under 16.

The charges do not relate to a current, or former, student at the college.

Court documents reveal Whittaker, 70, is accused of indecently and sexually assaulting the same young girl on multiple occasions at Russell Vale between March 1997 and March 2000.

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The girl was aged between 11 and 14 at the time of the alleged offences. Whittaker is accused of kissing the girl, touching her breast, groin and vagina, as well as having non-consensual sex with her.

In court on Monday, Magistrate Susan McGowan denied Whittaker bail, citing the strong case against him and the likelihood of a custodial sentence.

The matter returns to court on July 10.

On Wednesday, Catholic Education Diocese of Wollongong schools director Peter Turner told Holy Spirit parents about the criminal proceedings via a statement.

The statement - seen by the Mercury - did not name Whittaker, prompting one parent to voice concern about his identity being withheld.

Mr Turner did confirm the accused worked at Holy Spirit College and reiterated his charges "do not involve a student, past or present".

"The man has been denied bail and will not be returning to the school," he said.

Mr Turner reassured the school community and general public that the diocese's schools were "totally committed to the care and protection of children and young people".

"We have rigorous child protection processes in place ... and our practices, programs and responses to safeguard children are thoroughly planned and implemented," he said.