Mum helped her nephew rape her 12-year-old daughter by holding her legs down.

Warning: This post deals with rape and may be distressing for some readers. 

“This is gross offending. The breaking of the virginity.”

A court has heard that a Melbourne mother, 55, who was in a sexual relationship with her adult nephew, 42, helped him rape her 12-year-old daughter.

The pair who have pleaded guilty to the charges have appeared in court where details of the shocking crimes were revealed.

The court heard that the young girl told police she was crying and telling her cousin to stop, but her mother held her leg for a better view.

The pair who have pleaded guilty to the charges have appeared in court. Via Twitter.

Yesterday the Melbourne man pleaded guilty in the County Court of Victoria to persistent sexual abuse of a child under the age of 16. His partner, the girl’s mother pleaded guilty to sexual penetration of a child and an indecent act with a child.

The mother and nephew were in a sexual relationship when they started abusing the victim at the age of 12 in 2011.

Prosecutor Michael Hennessy told the court it was “gross offending,"

“The breaking of the virginity."

The Age reports that the mother and her daughter began to live with the man after she had split from her husband in 2011.

The relationship between the two started shortly after.

On one occasion, the court heard, while the pair were having sex, the nephew started touching the daughter. It was just after this that the young girl was raped for the first time.

"The girl is crying and it's hurting . . . and [the mother] holds the leg so she can see what's happening," Mr Hennessy said.

The rapes continued until 2014, when the girl was 15. They usually took place when the girl was alone in the house and her mother was not present.

A lawyer for the mother said it was a “gross violation of the relationship between a mother and her daughter."

The nephew and the girl’s mother were arrested in December 2014 after the daughter told her older siblings about the attacks.

The man was bailed but the mother has been on remand since March after she broke her bail conditions and contacted her daughter a number of times.

The rapes continued until 2014, when the girl was 15. Via IStock.

The nephew's defence lawyer, Ashley Halphen, said the nephew had expressed remorse in a letter to the daughter, who is now 17.

But the judge wasn't convinced.

"Reading the whole tenor of it, I don't see it," Judge Claire Quin said.

The case was adjourned until Friday.

For help: Lifeline 13 11 14. Kid's Helpline: 1800 55 1800. DV and Sexual Abuse hotline 27/4: 1800 737 732.