Parker opens up about her relationship with the Downton Abbey star in the book Lucky Me: My Life With - and Without - My Mom, Shirley MacLaine, and throughout the tome she describes the 78 year old as an absentee mum with tough-love parenting techniques and delusions about aliens.
The 56 year old knew the project would only make their relationship more strained, but she felt compelled to tell her story, saying, "I did everything I could to bring Mom into my life. The Hollywood ending never happened. Now that I've written this book, it probably never will."
And now the movie veteran has spoken out to condemn the book, insisting Parker, who is also an actress, just made sensational claims to get publicity.
A statement from MacLaine to People magazine reads, "I'm sorry to see such a dishonest, opportunistic effort from my daughter. (It's) virtually all fiction."
When Parker was two years old, MacLaine sent the tot to live with her businessman father Steve in Japan - and the 56 year old claims she hardly ever saw her mother.
During an interview on U.S. news show 20/20, she says, "She was very absent. I was very lonely - very lonely. Definitely. And I still struggle with abandonment issues and loneliness."
Parker alleges she returned home from boarding school one Christmas to find an empty house, and recalls, "I laugh now. But I have to say, at the time it was very scary and very painful. And I actually had a physical pain in my heart."
In her later years, she asked the Downton Abbey star, 78, for $500 (£312.50) to buy a used car - but MacLaine insisted on loaning it to her with interest.
Parker adds, "My mother was, is, very old-school regarding money and tough love."
She worked as a maid, waitress and stewardess in order to pay her university tuition fees and confesses it was always bittersweet when her mum's films came on mid-flight.
She says, "I would look up, and the in-flight movie would be The Turning Point or another (MacLaine) movie. And it would be a moment that I would find that I could be with her. She was right there. And I would just yearn for her."
Parker, who writes about their mother-daughter relationship in new memoir Lucky Me: My Life With - and Without - My Mom, Shirley MacLaine, last spoke to the icon in the summer of 2012 and admits she wants to patch up their relationship, adding, "I try to understand her. I find myself wanting to protect her so badly, because I so love her... And yet the pain is very deep. I would hope that she would own it and apologise. That would really, really be wonderful."