The Pro Life Campaign and the Iona Institute separately hit out at Taoiseach Enda Kenny’s confirmation that he plans to bring in legislation to tackle the issue, backed up by regulations.
The Pro Life Campaign said “any proposal” to allow abortion would inevitably, over time, lead to abortion on demand.
Spokeswoman Cora Sherlock said it was a “chilling prospect”, and meant her organisation must tackle politicians head on.
“The Government was always going to represent any proposals to introduce abortion as ‘very restrictive’. But the reality is they simply won’t be and can’t be.
“The X case decision heard no medical evidence and contains no duty of care towards the baby. Any such legislation proposed by the Government would for the first time introduce an abortion regime into this country in which the life of the baby could be directly and intentionally targeted for destruction.
“This is a chilling prospect. Once the principle of protecting human life is conceded, it leads inevitably to wide-ranging abortion.”
She added that her group will oppose any decision to introduce an abortion “regime”.
“While treating politicians with respect, we will mount a robust and sustained challenged to each and every element of the proposed legislation,” she said.
Last week, posters of what appeared to be a bloodied foetus and reading “Every child matters, except to Alan Shatter” were put up in Mr Shatter’s constituency. The posters did not refer to any specific group, but Mr Shatter called them the tactics of “fundamentalist bully boys”.
The Pro Life Campaign’s remarks were echoed by the Iona Institute, whose spokeswoman Maria Steen said it was “ironic” abortion is being discussed “on the cusp of Christmas when we celebrate the birth of a child”.
“Any decision to include suicidal intent would be unnecessary because it would not save a single life,” said Ms Steen.
“Irish law already allows the ending of a pregnancy when there is no other choice... A decision to include a threat of suicide as a ground for abortion would be wrong in principle because it would authorise for the first time ever the deliberate and direct destruction of unborn human life in Ireland.”
Independent senator Ronan Mullen said Fine Gael has broken pre-election promises by endorsing “the intentional killing of unborn children”.
“We must now renew our efforts to ensure the psychiatric myth of abortion as treatment for suicidal ideation is challenged by good ethics, accurate science, and responsible politics,” he said.