Fr Vincent Twomey, Emeritus Professor of Moral Theology at the University of Maynooth, described the clause allowing a conscientious objection as "passing the buck".
"It's the Pontius Pilate answer. 'I'm not going to do it but somebody else can do it for me'."
Prof Twomey said he hoped the Catholic hierarchy would "fight tooth and nail" to oppose the entire legislation.
Dramatic
He was speaking in the wake of comments by Cardinal Sean Brady that the proposed legislation was "potentially menacing" for hospitals and for the expression of religion throughout the country.
Catholic bishops have criticised the proposed legislation as a dramatic and morally unacceptable change to Irish law.
The hierarchy says the Protection of Life in Pregnancy Bill is unnecessary to ensure that women receive "the life-saving treatment they need during pregnancy".
They insist the Bill would make the direct and intentional killing of unborn children lawful in Ireland.
"The deliberate decision to deprive an innocent human being of life is always morally wrong," they add.
The bishops also have concerns about the Bill appearing "to impose a duty on Catholic hospitals to provide abortions" which they say would be "totally unacceptable".
This, they say, would have serious implications for the existing legal and Constitutional arrangements that respect the "legitimate autonomy and religious ethos of faith-based institutions.
"It would pose serious difficulties for the conscientious beliefs of many citizens."
Justification
In relation to pregnant women who were suicidal, the bishops emphasise "directly killing the unborn child is never a remedy for suicidal ideation and therefore should never be cited as a justification for the direct killing of an innocent human being.
"It
is a tragic moment for Irish society when we regard the deliberate
destruction of a completely innocent person as an acceptable response to
the threat of the preventable death of another person."
Cardinal
Brady believes that politicians "have an obligation to oppose the laws
that are attacking something so fundamental as the right to life and
they would have to follow their own conscience.
"We commend the efforts to protect the life of the mother, but who speaks for the life of the child?" he asked.
He would not be drawn on whether politicians who advocate support for the legislation should be barred from Communion.
Enforcing
the legislation across hospitals, however, "could lead to potential
legal action against the reforms. We believe that is a denial of
fundamental religious freedom."
Reacting to the bishops'
statement, Tanaiste Eamon Gilmore said that, while they are entitled to
their views, Ireland is a democratic country and laws are made by those
elected by the people.
He said for 21 years legislators
failed to legislate in circumstances where a pregnant woman's life was
at risk and that was now being addressed.