Fine Gael Senator Fidelma Healy-Eames has confirmed she will vote against her party on the abortion legislation later today.
Sen Healy-Eames said she has made the decision to vote against the party whip on the abortion legislation with a heavy heart and knowing what it means for her.
"I do want to exercise my human right to make a conscientious decision," she told the Seanad.
"Almost every western democracy provides for a free vote on moral issues like abortion.
"Why don't we have the confidence to trust our parliamentarians to make the right decision? I've been a committed member of Fine Gael for many years - the party that made a solemn promise to voters not to legislate for abortion.
"It saddens me greatly that Fine Gael have broken this promise."
The Protection of Life During Pregnancy Bill goes to a vote later today.