Abuse tutor 'remorseless monster': NSW mum

A Sydney mother whose children were repeatedly sexually abused by their mathematics tutor has told a court her feelings of guilt at allowing a "monster" into their home eat away at her every day.

Quy Huy Hoang was found guilty last November of 10 counts of sex crimes against four girls and one boy between 2007 and 2014.

Crown prosecutor Paul Leask on Friday told Sydney District Court he would call for the bespectacled, silver-haired former tutor to be sentenced to life behind bars.

In a heartbreaking victim-impact statement read out to the court, one mother described the day her children revealed their abuse as "the day my life turned upside down".

The court heard the woman's son had since told her: "I just want to die."

"When I asked why, he said, 'It's because I get flashbacks'," she wrote.

The little boy's sister was also abused by Hoang from the age of seven, the court heard, and still has trouble sleeping in her own bedroom.

"My daughter has told me numerous times that the room is haunted and that bad things happen there," the children's mother said in her statement.

She told how she was tormented by her feelings of guilt for trusting Hoang and leaving him alone with her children.

"I was responsible for bringing this monster into my home," she said.

"The guilt is eating at me."

She said Hoang had shown no remorse and had "never, ever" offered an apology.

A psychologist has given evidence that she believes Hoang is a "sophisticated" predator who spent months gaining the trust of the families he targeted.

The sentencing hearing continues before Judge Kate Traill.