The priest, Father Noel Geraghty of the Catholic order Oblates of Mary Immaculate, died in 2005 without the long-term relationship being acknowledged in public by the Church, although it has confirmed it in writing to the nun's family.

There is evidence the former nun, 70, who has been in care from the age of 63, was not the priest's only female sexual partner.

The former nun's brother, a retired teacher who lives in the Hunter, is speaking about it for the first time as the Church faces a new crisis - exposure of its male clergy's forbidden, secret and abusive relationships with adult women.

"There are so many women out there in this position," said the former nun's brother, David, who asked that the family's identity not be disclosed.

"He would sit at our table, come in and enjoy the hospitality of my parents, and all that time he was in a sexual relationship with my sister that he never acknowledged. It's sick."

David's decision to speak follows Newcastle Herald articles last week about Jennifer Herrick, the Central Coast woman trying to break legal ground in a NSW Supreme Court case against a priest that her lawyer hopes will compare secret sexual relationships between priests and vulnerable women with abusive relationships between doctors and women patients.

Mrs Herrick is supported by Australian Catholic University theology professor Neil Ormerod, who said this week that the number of abusive relationships between priests and women in Australia was "the great unknown question for the Catholic Church", but "I'm sure it's far more prevalent than child sexual abuse cases".

"A lot of the Towards Healing cases the Church are dealing with now are in the realm of adult relationships. They're abusive because there's always a power imbalance between priests and the women. And while the priests are supposed to be there to meet the pastoral needs of the woman, they're actually using the relationship for their own needs."

David said his sister entered a convent to become a nun in 1960, aged 17, two years after the relationship with Noel Geraghty started.

"Noel Geraghty claimed, and my sister accepted, that she had seduced him. He was 35 and she was a sexually naive 15-year-old virgin from a very Catholic family," David said.

"She told us years later that she became a nun because if she couldn't have Noel, she would have his lifestyle.

"He was happy to allow her to take responsibility for him breaking his priestly vows so that she felt guilty of wooing him from the altar. At one point she said, 'That poor man, he's got such pressures on him.'."

David's sister remained a nun for nine years. Shortly after she left the order she was in a serious car accident.

"When she regained consciousness, the first thing she said was, 'Tell Noel'."

The relationship continued and remained a public secret, although the family tried to intervene. She would not discuss it until her later years.

"She kept herself available, all through her life, but she was only available for him. He took pride of place."

For the past four years, while the former nun has suffered the effects of advanced dementia, her brother and sisters have sought a meeting with the Victoria-based Oblates.

Although the order wrote to the family about having a meeting, it was never organised.

"In the end, they offered us Towards Healing. We rejected that," David said.

"We've agreed to speak about this now because the church is not willing to speak with us as a family who grew up in their care. We never approached them aggressively, making demands or wanting compensation."

The family believes there are other women leading troubled lives because of their contact with the priest, and they want his order to acknowledge that.

"Our sister remained single for Father Geraghty. He maintained that hold on her. Otherwise she might have had a partner of her own, and a family to support her now. She was in nursing care by the age of 63," David said.

"She was taught to deny, hide and lie about herself by Father Geraghty. Denial and secrecy would be a big part of her growing up because of him.

"Because of her dementia, she has let the tragedy of her story go, but her siblings haven't. We want to tell her story."

IN the obituary for Father Noel Geraghty after his death in June 2005 his order, the Oblates of Mary Immaculate, described him as ‘‘a man of simple but deep faith’’.

He was ‘‘approachable to young and old, to men and women alike, and he was never known to hurt people or to offend them in any way’’, the obituary said.

‘‘He had an extraordinary gift for unashamedly asking people many questions about the details of their life.’’

The obituary failed to mention his secret, forbidden sexual relationship with at least one woman.

In a letter on March 12, 2009, to David, the brother of the former Hunter nun who was in a sexual relationship  from the age of 15 with Father Geraghty, Sydney Archdiocese Chancellor Father John Usher said her story was very believable and  needed  to be acknowledged. 

‘‘The most alarming aspect of the story is the way the priest used his ‘power’ and his position of trust to gain a young girl’s affection and then betray that trust by sexually abusing her,’’  Father Usher  said.

‘‘No such relationship with an under-age girl involving an older person, let alone a priest, should be described as consensual. I am sure you will agree with this and the whole matter needs to be redefined as sexual abuse.’’

On November 24, 2009, Father Usher told the former nun’s family that Cardinal George Pell had written to the head of the Oblates of Mary Immaculate to suggest the head of the order, or his NSW delegate, meet  the former nun’s brother, David,  and other family members.

‘‘We haven’t had the meeting,’’ David said.

The order did not respond to Newcastle Herald questions.  

A PRIEST called in to investigate the relationship between Father Noel Geraghty and a 15-year-old girl was later investigated by police for serious child sex offences against girls at notorious Brisbane orphanage Nazareth House.

‘‘Father John O’Regan smoothed the waters with my mother in 1959 after she called him because of her concerns about my sister and Geraghty,’’ said David, the girl’s brother.

‘‘Father O’Regan was an acquaintance who had visited us often.’’

One year later the girl  entered a convent to become a nun. The sexual relationship with Father Geraghty continued until many years later.

In 1998 several former Nazareth House residents told the Queensland Children’s Commission they had been sexually assaulted by Father O’Regan and two other priests at the orphanage in the 1950s and 1960s.

A woman alleged she was sent alone to Father O’Regan when she was 13 to be taught the facts of life.

‘‘He mauled my body sexually, told me not to tell anybody and said it was our secret,’’ she told the children’s commission.

Father O’Regan, a colleague of Father Geraghty from the order Oblates of Mary Immaculate, provided ‘‘counselling’’ to Nazareth House residents. Queensland police sought to talk to Father O’Regan in September 1998 about the allegations. But he died the following month.