TD Carol Nolan has been suspended from Sinn Féin for three months for voting against party policy on abortion.
The Offaly TD yesterday voted in the Dáil against legislation to allow a referendum on the Eighth Amendment.
The amendment to the Republic's constitution gives equal weight to the life of a mother and her unborn child.
Sinn Féin supports scrapping the amendment and will be campaigning for a repeal vote in the forthcoming referendum, scheduled for late May.
Sinn Féin leader Mary Lou McDonald said she recognised Ms Nolan's strong anti-abortion views.
"At all stages, the party has acknowledged and respected her views and her right to articulate those views," she said.
"However, Sinn Féin elected representatives are expected to respect policy decisions taken by the Ard Fheis and to vote in line with party policy.
"All Sinn Féin elected representatives, including members of the Oireachtas, are aware of this.
"Carol is a valued colleague and I very much regret this turn of events.
"However, as legislators we have a responsibility to vote as we are mandated by long standing Sinn Féin policy, a policy which we strongly believe is in the best interests of women."
Meanwhile, the bill to allow for a referendum on changes to abortion legislation yesterday passed its latest stage in the Dáil.
