The Taoiseach, Mr Ahern, and the Minister for Foreign Affairs, Mr Cowen, have described Thursday night's bombing in London as an attack on the peace process that will not succeed.
In a statement yesterday Mr Ahern said the bombing "will not deter both governments, the pro-agreement parties and the overwhelming majority of the Irish people who seek peace on this island.
"We utterly reject the motives of those responsible and will not allow them to thwart the progress in resolving all outstanding issues in the peace process," he said.
Mr Cowen said the bombing was a "a senseless act" which was "another example of the actions of those who have nothing to offer except death and destruction". He described the bombing as "a sinister attempt to undermine the peace process at a time when all democrats are actively trying to chart a way forward out of the current difficulties affecting the full implementation of the Good Friday agreement."
The Fine Gael leader, Mr Michael Noonan, called it "an appalling act by a group which represents nobody.
"The Good Friday agreement was endorsed by the majority of people, North and South, and there is absolutely no justification for any group carrying out a further campaign of violence."
The Labour Party leader, Mr Ruairi Quinn, said the attack was "an evil and criminal act, perpetrated by those who have nothing to offer the people of Ireland".
"Those who carried out this attack, and other groups responsible for recent sectarian murders in Northern Ireland, will be only too willing to take advantage of any political vacuum in Northern Ireland.
In these circumstances it is all the more essential that all political parties and paramilitaries respond in the most positive way possible to the proposals produced this week by the British and Irish governments."
The Northern Ireland Secretary, Dr John Reid, said he hoped that far from being deflected by the bomb attack all parties would redouble their efforts to reach agreement.
"The people who did this have nothing to offer except more hatred and division. They have no strategy, they have no support," Dr Reid said.
The Sinn Fein leader, Mr Gerry Adams, said the party was "resolutely opposed" to the London bombing. Distancing the party from the violence by dissident republicans, he called "on those involved in these actions to stop".
Extending sympathy to the injured, he said "anyone who styles themselves as a republican - any real republican would be involved in trying to build upon the opportunities for peace and justice which are part of this process and which this party's leadership and others are engaged in".
Ulster Unionist MP Mr David Burnside urged the government to bolster policing both in London and the North. Rhetoric about political dialogue will not stop terrorism, he said.
The SDLP chairman, Mr Alex Attwood, described the Ealing bomb as a "very disturbing development". "Fortunately, there have been no fatalities, but clearly there is a very high risk, and people need to show very high vigilance, both the public and the police, in terms of addressing this."