The sister of singer Mary Coughlan has publicly challenged claims made by the entertainer in a new autobiography. Angela Magennis says she is "saddened and angry" at the portrayal of her family in book Bloody Mary: My Story.

"Since I got a copy of Mary's book last Saturday and began to read it through, I have felt totally saddened and angry at her portrayal of our family and frustrated by the fact that the book was published without any member of the family having had prior sight or the opportunity to refute allegations made," Magennis said.

"The title of the book is apt - Bloody Mary: My Story because it is that - a story. It is full of inaccuracies, embellishments and convenient omissions. I do not want to get into a slagging match with my sister, but she has put a book out there, and in doing so, invites comment. For me to make no comment would be to suggest that every­thing in the book is true and accurate."

Magennis's objections to the book include the portrait Coughlan paints of their mother growing up in Galway. In the book's prologue Mary Coughlan writes how, following her mother's death in October 2004, she accompanied her body in the hearse leaving Galway's Regional Hospital. She writes: "With my composure intact, inside I'm screaming at my mother in the back of the car. 'You did f**k all for me when you were alive, so now you're dead, you better f***king help me'..." and claims, in passages about her childhood, that she was affected by the severe depression her mother suffered as a result of the death of a baby.

Magennis contradicts this. "Our mother couldn't have done more," she said. "Mary was 15 years old when my mother lost a baby in 1971. That is when depression hit my mother. At the start of chapter five, Mary says 1971 was when she started taking acid and hanging out in Eyre Square. The book makes no sense at all, it is all over the place."

Magennis is also furious at Coughlan's depiction of their father as a violent man who regularly beat Mary.

"My father is 80 years old and devastated by this book. The father in the book isn't the father I recognise who worked two or three jobs to support us. My parents were kind and loving. Reading the book you would think we were growing up in separate houses. All the people who have lived with Mary, looked after her, cherished and supported her both financially and emotionally since the day she was born to the present day, do not deserve to be betrayed in this manner. She has done herself and her family a disservice.

"I am glad for her [Mary] that she is finally clean and sober and I wish her well in her music career. I greatly admire anybody who has overcome abuse and drink and alcohol addiction and who goes on to live full and meaningful lives."

Contacted by the Sunday Tribune Mary Coughlan said: "I don't want to talk about this. I wrote the book. I have nothing to say."