Former Fine Gael TD Monica Barnes has died at the age of 82.
She served as a TD for Dun Laoghaire for 15 years after being first elected to the Dáil in 1982.
President Higgins said Ms Barnes was a proud feminist who championed women's rights throughout her parliamentary career and beyond.
The Taoiseach, Leo Varadkar, praised her for her dedication to women's rights.
"She was always willing to speak her mind and she was a fearless campaigner for change, at a time when it was not always easy," he said.
Fianna Fáil Leader Micheál Martin TD has said that the untimely death of former TD for Dun Laoghaire, Monica Barnes is a loss for Irish politics.
"Monica was a courageous and outspoken voice in Irish politics at a time when progressive voices were few and far between," he said
Monica Barnes had been due to speak at an event about the 8th amendment tomorrow, having campaigned vigorously on the issue in the past.