A man charged with 173 counts of rape and sexual assault of three of his partner’s children over the course of a decade has been given a 15 year sentence with three years suspended.

The 61-year-old man, who cannot be named to protect the identities of his victims, pleaded guilty at the Central Criminal Court to all offences committed at various locations between 2001 and 2010.

The man, who has two previous convictions for sexual offences, was in a relationship with the children's mother.

The court heard that the sexual abuse began when each of the three siblings reached the age of six or seven.

Neither the boy nor his two sisters were aware that the others were being abused.

Mr Justice Paul Carney said the case involved "nearly every form of depravity it is possible to perpetrate on children."

Harrowing victim impact statements for each of the three victims, now in their late teens and early twenties, were read out in court.

The siblings said they felt their childhood was ruined and their innocence stolen from them.

They remain terrified of swimming pools, caravans, graveyards and bogs and other places where they were raped and assaulted.

The eldest sister said she felt so alone and afraid as a child and that she had no-one to turn to.

"I felt like it was my fault. I trusted him and he let me down and hurt me in the worst possible way," she said.

The girl said she feels jumpy and paranoid all the time, and that she is afraid to walk out the door because she thinks people are looking at her and talking about her.

Her younger sister, now aged 18, said she feels like she is in a "dark hole" and can not get out of it.

"I wish sometimes I was never born," said the girl. She said she still has a lot of nightmares and remains very nervous every time she has a shower or a bath as she is afraid her attacker will be waiting for her.

She said she has no confidence and does not think she will ever trust a man again.

"This has destroyed my whole family," she said.

The 18-year-old boy said he felt suicidal at times because he was not able to cope with the abuse.

He said he turned to alcohol and later drugs, but that with the help of his foster family he no longer takes drugs.

"I hate myself for acting like a coward because I never did much to stop the abuse. I feel like less of a man," he said.

The boy said he is afraid that people won't trust him and that he won't be able to have relationships with girls in the future.

Delia Flynn SC, defending, said her client was placed in foster care at a young age and spent a number of years in institutions.

Ms Flynn said he suffered from depression as a result of his childhood experiences. He has attempted suicide and been hospitalised afterwards.

She outlined a number of serious health issues and said he was "a man in a state of considerable physical debilitation."

Mr Justice Carney said he was taking into account a range of factors including the breach of trust, the victim's ages, the multiplicity of victims and offences, the effect on the children, the relevant previous convictions and the involvement of other men in some of the offences.

He imposed a 15 year sentence and suspended the final three years taking into account the man's guilty plea.