The Taoiseach has said "unequivocally and without reservation" that he completely condemns the "disobedience and non-cooperation and contempt in respect of which Deputy Lawlor was found guilty".
In a letter to the Fine Gael leader, Mr Ahern said he entirely endorsed the sentiments of Mr Justice Thomas Smyth.
Mr Ahern also said that Mr Lawlor's failure to meet the requirements of the Courts and the Flood Tribunal would confirm his membership of the Dáil to be untenable.
The Government is to table a Dáil motion calling on the Dublin West TD to resign his seat if he does not fully co-operate with the Flood Tribunal within the time-frame set down by the High Court judge.
Mr Ahern was responding to Mr Bruton's call for an all-party statement urging Liam Lawlor to resign from the Dáil.
The Taoiseach said that it was the Government’s view that the sentence had been structured to elicit Mr Lawlor's full co-operation within a definite time-frame. The Government believed that Deputy Lawlor should fully meet the requirements of the courts and the tribunal. Failure to do so would confirm his membership of the Dáil to be untenable and he should voluntarily resign his seat.
But tonight Mr Bruton said the Taoiseach had crafted a reply to his letter that "deliberately misses the whole point".
In a statement Mr Bruton said: "Deputy Lawlor was elected as a Fianna Fáil Deputy in 1997, but his continuance as a TD does not reflect the wishes or intentions of the people who elected him. The leader of Fianna Fáil has, in his letter to me, gone to inordinate lengths to avoid making that simple, democratic point."
He accused the Taoiseach of working out an elaborate and evasive formula designed to give the Government the appearance of distancing itself from Deputy Lawlor, while still allowing it to continue to call on his vote in Dáil Éireann.