Fine Gael party chairman Charlie Flanagan has compared extremist anti-abortion campaigners to the Ku Klux Klan.
Mr Flanagan was responding to Fine Gael TDs being personally targeted by anti- abortion campaigners who are putting up posters outside their homes, offices and even local churches.
The posters usually have a picture of the TD, the Fine Gael logo and a picture of a foetus in its mother's womb but no identifying marks to say who produced the poster.
Mr Flanagan hit back at the practice saying: "Abortion posters with FG TDs appear in the night. Nobody admits to putting them up. Promoters hide their faces. Just like KKK," he said on Twitter.
The chairman of the Fine Gael parliamentary party said he won't be intimidated by "faceless bullies who peddle deception and lies under the cover of darkness".
Fianna Fail looks set to vote against the legislation after party leader Micheal Martin failed to get a critical mass of his TDs and senators to support the Coalition's approach.
Mr Martin had wanted to support the bill, but his TDs and senators are almost split down the middle. It puts the party leader in a difficult position and facing the prospect of losing Oireachtas members if he imposes a whipped vote.
Senator Diarmuid Wilson was said to be the most passionate voice against the legislation, utterly ruling out voting for it, while others opposed included TDs Michael McGrath, Dara Calleary, Robert Troy, Eamon O Cuiv, Seamus Kirk and Sean O Fearghail, and senators Terry Leyden and Labhras O Murchu. TDs John Browne and Brendan Smyth are also in the anti-legislation camp.