Sinn Féin leader Mr Gerry Adams today challenged the Taoiseach to order his arrest or else withdraw his charge that his party had prior knowledge of December's Northern Bank heist.
Reacting angrily to today's Independent Monitoring Committee's report (IMC) blaming the Provisional IRA for the £26.5 million heist, Mr Adams challenged Mr Ahern to "shut up or put up" after a Government statement said the report endorsed their position.
Mr Ahern has claimed Mr Adams and other members of the Sinn Féin negotiating team knew the robbery was being planned during December's peace talks which collapsed at the last minute.
This evening, a spokesman for the Taoiseach said Mr Ahern did not have the power to order arrests and that such matters must be dealt with by the police.
"Anybody familiar with the rule of law in this country would know well that the Taoiseach has no power to direct the arrest of anyone.
"Operational aspects of the investigation of the Northern Bank robbery and the other crimes referred to by the IMC report were entirely a matter for the police forces in both jurisdictions."
The Irish and British governments accept the PSNI Chief Constable Hugh Orde's claim that the IRA was behind the robbery and have since taken a less compromising line with the republican movement.
Sinn Féin have repeatedly denied the claim and says no evidence has been produce to back the claim.
Today's IMC report backed Mr Orde's contention and also said members of Sinn Féin's ard comhairle were on the Provisional IRA army council. It recommended that Sinn Féin members of the Asssembly should have their pay suspended under the terms of sanction in the Belfast Agreement.
Mr Adams rubbished the report, claiming the IMC to be a biased tool of the British and Irish governments, made up of "three spooks and a lord".
"The report is rubbish. The report makes unsubstantiated allegations. If it wasn't so serious it would be even laughable.
"I feel a particular sense of betrayal by the Taoiseach. I think the Taoiseach has crossed the line and the line that he has crossed - and I took legal advice on this - was to accuse Martin McGuinness and I of conspiracy to rob and of withholding information. I feel particularly angry about that."
When asked if he was challenging the Taoiseach to have him arrested for the Northern Bank robbery, he replied: "That is the only logical thing that the Taoiseach can do. I don't go for the wink and nod politics."
Mr Adams accused Mr Ahern of "dirty politics" and demanded he withdraw the allegations or else have him charged.
"I think the Taoiseach has crossed the line. It's time for him to shut up or put up," the Sinn Féin president said outside Leinster House today.
Meanwhile, there were a number demonstrations across Northern Ireland in protest at the IMC report.