A judge has criticised the Director of Public Prosecutions for delays in processing the case of a man who sexually assaulted his 12-year old daughter and her friend.

Judge Mary Ellen Ring was speaking at Dublin Circuit Criminal Court as she sentenced a 39-year-old man to three and a half years in prison.

The court heard that after the victims made allegations of abuse, the man went voluntarily to gardaí in January 2012 and admitted sexually assaulting his daughter over a year-long period.

He also admitted assaulting his daughter's 13-year-old school friend once when she stayed in his house on a sleepover.

The man, who cannot be named to protect the identity of the victims, pleaded guilty to five sample counts of sex assault of a total of 26 counts, carried out between January and December 2011.

Judge Ring said despite the best efforts of the gardaí, it took a further 15 months for the DPP to prosecute the case while the lives of the victims were put on hold.

She asked prosecuting barrister, Fiona Murphy BL, to bring the issue to the attention of the Director.

“The system has to move with some priority when we are dealing with young people. Something has to be done. It needs to be sorted out. These two people just wanted to get on with their lives,” she said.

One of the victims, now aged 16, read aloud a victim impact statement detailing how her life changed after she was abused by her friend's father.

She said she felt worthless and began having suicidal tendencies and had tried to kill herself a few times.

The teenager said she was hospitalised, missed most of her first two years at secondary school, lost her confidence and was bullied.

The man's daughter was abused regularly when she went to stay with her father.

In a victim impact statement read out on her behalf, she said she became suicidal, depressed and self-harmed. She developed an eating disorder, her grades dropped and her relationships with her friends and family suffered. She said she still becomes anxious and panicky around older men especially if they drank.

Philipp Rahn BL, defending, said his client, who has no previous convictions, had himself been sexually abused when he was 12 or 13.

He said the accused man suffered from depression and has been unemployed for a number of years. A forensic psychologist told the court the accused had attended therapy for the last two years and was at a low risk of re-offending.

Garda Sarah Donnelly said the abuse came to light after one victim told her mother that her friend's father had abused her while she was staying over in October 2011.

The girl's mother contacted gardaí and some months later the other victim was told by her mother that her friend had made an allegation of abuse.

The girl started roaring crying and said her father had done the same to her for the past year.

She later told gardaí that whenever she stayed at her father's house over the previous year, he would sexually assault her three or four times over a weekend. She said she was shocked and confused and wanted it to stop.

The accused man presented to gardaí in January 2012 distressed and crying uncontrollably, saying he wanted to “come clean”. He told gardaí he felt sick and ashamed and apologised for the pain he had caused the victims.

Judge Ring said both girls had suffered as a result of the abuse, and that the man's daughter had suffered the most fundamental breach of trust.

She credited both teenagers for bringing the abuse to an end. She also gave credit to the accused for the work he has done to rehabilitate himself.

Judge Ring ordered that he be placed on the sex offenders' register.