A MELBOURNE mother in a sexual relationship with her adult nephew helped him rape and “break the virginity” of her 12-year-old daughter.

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

None can be named for legal reasons, but the man, 42, pleaded guilty in the County Court of Victoria on Wednesday to persistent sexual abuse of a child under the age of 16.

The 55-year-old woman 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 the offending started in 2011, when the victim was 12.

“This is gross offending. The breaking of the virginity,” prosecutor Michael Hennessy told the court on Wednesday.

The mother and her nephew began their relationship shortly after he let the woman and her daughter live in one of his houses after she had split from her husband in 2011.

On one occasion while the pair were having sex, the nephew started touching the daughter.

The daughter was raped for the first time shortly after.

“The girl is crying and it’s hurting while the virginity is broken, 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, although the mother was not involved again. It was usually when the girl was alone in the house.

“(It was) a gross violation of the relationship between a mother and her daughter,” the mother’s lawyer, Stephen Lindner, told the court.

The nephew was arrested in December 2014 after the daughter told her older siblings about the attacks.

The nephew 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 nephew’s defence lawyer, Ashley Halphen, said the nephew had expressed remorse in a letter to the daughter, who is now 17. Judge Claire Quin wasn’t convinced.

“Reading the whole tenor of it, I don’t see it,” Judge Quin said.

The hearing was adjourned until Friday.