The abuse came to light after the woman's husband walked in on her and the youth having intercourse.

The woman, who cannot be named as that would identify the victim, appeared in the Warrnambool Magistrates Court ​on Wednesday for a committal hearing.

She was originally charged with four counts of both incest and sexual penetration of a youth under her care and supervision.

It was alleged those offences were committed between November 1, 2016, and March 13, 2017

On Wednesday the prosecution amended one charge of incest involving a step-child – to having been committed on March 13 last year.

The other seven charges were withdrawn.

Magistrate Cynthia Toose ordered the woman to appear in the Warrnambool County Court during the next sitting starting on June 4.

But that plea hearing may not be reached due to the backlog of cases and could be adjourned until the sittings in October. 

The woman had previously indicated she would be vigorously fighting the charges.

She has been released on bail with the conditions she live in Warrnambool, surrender her passport, not attend points of international departure, she can only see two of her children through supervised contact but can ring them every second Friday.