At least two and possibly up to six senators are expected to lose the party whip, which will see them expelled from the parliamentary party.
Senators are unlikely to have a final vote on the bill until at least Monday week.
Rebel senators hope their opposition to the Protection of Life During Pregnancy Bill will force its return to the Dáil late next week. However, it remains unclear if opposing senators will be able to get enough support from colleagues to block its passing in the Seanad.
Party senator Fidelma Healy Eames told the Irish Examiner that she will table a “reasoned amendment” on Monday when the legislation is brought before the Seanad. This objects to the general principle of the bill and will oppose its second reading in the house.
The amendment will be backed by Independent senators Fergal Quinn and Mary Ann O’Brien. Fine Gael senator Paul Bradford is expected to support the opposing amendment. Mr Bradford is married to TD Lucinda Creighton, who was expelled from the parliamentary party this week and lost her position as a minister after opposing the bill in the Dáil.
Ms Healy Eames said: “Obviously we know the result [of the votes on the bill]. My job is to try and improve it. We’re not trying to force anything back on the Dáil but it might have to reconvene. This is the way democracy works. As things stand, I will be expelled.”
Her amendment will say that it is “dangerous, irresponsible, and unjust” to legislate for abortion for women who are suicidal.
Fine Gael senators Michael Mullins, Tom Sheahan, and Michael Comiskey have also indicated they may oppose the legislation.
Fine Gael Seanad whip Paul Coghlan has also indicated his concerns about the bill and is expected to express his opposition during hearings next week.
However, at least two Fianna Fáil senators are likely to back the bill and it is unclear how the Taoiseach’s nominees will vote in the Seanad.
With the support of Sinn Féin, the Government is likely to pass it through.
The Coalition won the abortion legislation Dáil vote by 130-24. However, Fine Gael lost five TDs, including Ms Creighton.
Taoiseach Enda Kenny has warned Fine Gael Oireachtas members that they will not be allowed run for re-election under the party banner if they oppose the bill.