The Labour leader, Mr Ruairí Quinn, has called on the Taoiseach and the Catholic hierarchy to publish their conflicting legal advice about the status of the morning-after pill.
And the party's health spokeswoman, Ms Liz McManus, has dismissed as "quite laughable" a statement by the Minister for Health, that the Opposition had failed to spell out what abortion laws they would enact if returned to power. Such legislation was "not rocket science", she said.
Her party would legislate in line with the X case as recommended by the Government's Expert Review Group.
They were speaking in the RHA Gallery in Dublin, where the Labour Party rallied some 60 of its members in the campaign for a No vote on the deeply divisive issue of the abortion referendum.
Mr Quinn called on the hierarchy to publish its legal advice, which he said "directly conflicts with the words and advice we are hearing from the Irish Government".
His comments follow an interview on RTÉ Radio's This Week, on which the Bishop of Limerick, Dr Donal Murray, said he did not see how the morning-after pill would be given additional protection by the referendum.
"Our advice is we can't see that it weakens the position in any way of the embryo before implantation." The morning-after pill is used as emergency contraception to prevent implantation.
Mr Quinn said the Catholic Church was the Government's biggest supporter in the referendum and should publish its legal advice to contribute to the debate.
Using a cardboard cutout of the Taoiseach, Mr Quinn said Mr Ahern had the "mute button on" and was refusing to debate the referendum.
The only decision being made was whether "the threat to a woman's life arising from suicide should remain a ground for abortion in this country".
The Taoiseach, he claimed, had sought to "cloud the issue", by getting people to believe the referendum was about "whether we are pro- or anti-abortion".
Speaking after the rally, Ms McManus said her party would legislate in line with the X case, as recommened by the Expert Review Group, including Prof Ken Whittaker and the former Attorney General, EU Commissioner Mr David Byrne.
"They are not pro-abortion by any means," but they recommended legislation. The former Taoiseach, Mr Albert Reynolds, she said had produced the heads of a Bill, before the last referendum.
The party's MEP Mr Proinsias de Rossa, said the whole motivation for the abortion debate was driven by misogyny. "Ireland has always been a cold place for women and this referendum is making it even colder."
