Ms O'Brien died yesterday in London after a long illness.
She was a leading light for a generation of Irish writers, and her loss will profoundly impact the Irish literary scene.
President Michael D Higgins has led tributes to her, saying her work "has been sought as a model worldwide".
He described Ms. O'Brien as "a fearless teller of truths" and "a superb writer possessed of the moral courage to confront Irish society with realities long ignored and suppressed".
"Through that deeply insightful work, rich in humanity, Edna O'Brien was one of the first writers to provide a true voice to the experiences of women in Ireland in their different generations and played an important role in transforming the status of women across Irish society," he said.
President Higgins added that it is "important to remember the hostile reaction" that her work provoked among "those who wished for the lived experience of women to remain far from the world of Irish literature".
Her books, he said, were "shamefully banned upon their early publication".
"Thankfully Edna O'Brien's work is now recognized for the superb works of art which they are," he said.
"That work will continue to celebrate the full freedom that a writer must have, the risks and contradictions of circumstance, the release into beauty that imagination makes possible," he added.
He expressed his condolences to her children, family and friends.
Taoiseach Simon Harris paid tribute to Ms O'Brien describing her as "a brave, gifted, dignified and magnetic person".
"Ireland has lost an icon," he said.
Mr. Harris said that The Country Girls is "a remarkable piece of work but still a landmark moment for Irish women and society".
In a statement, he said: "Most people would have stopped and hidden away from the misogyny she faced, but Edna O’Brien kept working on her artistry and became one of modern Ireland’s most celebrated and honored writers".
"I want to express my heartfelt condolences as Taoiseach on the passing of such a special person," he said.
The vitality of her prose was a mirror of her zest for life: she was the very best company, kind, generous, mischievous, brave."
It was Faber’s "huge privilege" to publish her, they said, adding that her "bold and brilliant body of work lives on".
In a career spanning more than 60 years, Ms O'Brien wrote more than 20 novels and worked well into her 90s.
Such was the universal appeal of her portrayal of women's experiences, that she received France's highest cultural distinction in 2021.
She wrote The Country Trilogy among other books, plays, and short stories.
Her frank treatment of sexuality in the trilogy of novels that began with The Country Girls and included The Lonely Girl and Girls in Their Married Bliss, shocked Irish society.
Several of her novels were banned by the Irish censor.
The treatment of The Country Girls book ensured that Ms. O'Brien and the book became, for Irish novelist Eimear McBride, "era-defining symbols of the struggle for Irish women's voices to be heard".
Ms O'Brien also wrote five plays and four works of non-fiction.
Her latest novel, "Girl", a 2019 tale about the girls kidnapped in Nigeria by Islamist Boko Haram militants, included research trips to West Africa while in her late 80s.
