The Taoiseach, Mr Ahern, tonight issued a statement on the Al Jazeera Network calling for the release of Mr Kenneth Bigley, the British hostage threatened with execution in Iraq.
Mr Ahern said Mr Bigley was an "ordinary working man" who did not deserve to be harmed in any way.
Mr Bigley, whose mother Elizabeth is from Dublin, is being held by supporters of Abu Musab al-Zarqawi, a group that has made the release of female Iraqi prisoners a condition of his release. The group beheaded two American hostages earlier this week.
Mr Ahern said: "The Minister for Foreign Affairs, Brian Cowen, has been briefed in detail on developments in relation to Mr Bigley's case by Foreign Minister Straw and we are maintaining close contact with the British authorities on an ongoing basis.
"In addition the Irish Ambassador in London has at my request, communicated the sympathy and support of the Irish people at this time to the Bigley family, especially in the context of the family's Irish connections".
"Mr Bigley's family have summed up the circumstances perfectly in describing Mr Bigley as an ordinary working man. There is every reason to release him and no justifiable reason for causing him harm. I would appeal to Mr Bigley's captors to return him safe and sound to his family," the Taoiseach added.
Earlier today Mr Bigley's brother said that he still believes the Irish Government could be the "catalyst" to secure his release.
Mr Paul Bigley told the Gerry Ryan show on RTE radio this morning: "He's from Irish descent and it's a neutral government."
"We need to get a dialogue going and it needs to come from Dublin," he added.
Ms Elizabeth Bigley (86), was briefly hospitalised last night after breaking down in tears during a televised appeal for mercy last night. Mrs Bigley lives in Liverpool but is originally from Ticknock, south Co Dublin.
Up until this evening the family had received vocal support from Labour TD Michael D Higgins, who when talking to ireland.comearlier today said that he was willing to negotiate and travel to Iraq on behalf of Mr Bigley but that "we have to wait and see how things are shaping up."
Speaking on RTE radio, Mr Higgins called the US and British refusal to negotiate with the group holding Mr Bigley "contradictary and appalling".
"Issuing blank statements as they [the US and British authorities] did yesterday such as 'we never negotiate with terrorists' are inconsistent with the historical process."
Mr Paul Bigley said today he believed Mr Higgins's interview on Al-Jazeera provided a stay of execution for his brother. "I know the people who have got Ken have read this and this is why we have a stay of execution. We've got to get this thing moving.
"We have to get a dialogue going, I believe Michael [D. Higgins] is the man to head this and I've got my bag packed and I'll go anywhere in the world with him."
Meanwhile a Palestinian prisoner held in Britain under terrorism legislation has also appealed for Mr Bigley's release.
In a statement to Al-Jazeera, Mahmoud Abu Rideh called upon kidnappers in Iraq to free the "ordinary man with a family".
Rideh said he knew what it was like to suffer "injustice and torture", and could guess at the "great wrongs" happening in Iraq.
He claimed he was being held under "unjust laws", but that his quarrel was with the British government, not the people. He said: "I ask you to release the man you hold. He is half Irish, and he is an ordinary man with a family.
"I know that millions of British people did not and do not support the war on Iraq. A million marched against it last year.
"More than 6,000 British people have written to me to support me. They quarrel with the British government about injustice, and so do I.
"I do not quarrel with the British people. Our problem is with the government. Please release this man."
Britain has ruled out negotiating with the kidnappers and the United States has confirmed it will not allow the release of the female scientist Dr Rihab Rashid Taha who is imprisoned in Iraq.