Former taoiseach Bertie Ahern and Sinn Féin president Gerry Adams are in the Basque country today to take part in an international initiative aimed at assisting a resolution of the conflict there.
The conference in San Sebastian, which has been organised by a number of peace groups, will also be attended by former UN secretary general Kofi Annan; Tony Blair’s former chief of staff Jonathan Powell; former French defence minister Pierre Joxe; former Norwegian prime minister Gro Harlem Brundtland and others.
The last of Western Europe's main armed paramilitary groups, Eta is increasingly coming under pressure from disenchanted Eta prisoners and political allies to go further than a "permanent" ceasefire declared in September 2010. It has killed 829 people in bombings and shootings since the late 1960s.
It is classified as a terrorist organisation by Spain, the European Union and the United States. It declared a permanent ceasefire in January.
Mr Adams said the initiative was the consequence of considerable behind the scenes efforts by Sinn Féin and others, and he expressed hope that it would lead to significant progress in resolution of the conflict.
Spain's Socialist government is not supporting the conference but Basque socialists will attend. The government has repeatedly said it will not negotiate with Eta, which has declared and broken ceasefires in the past, unless it definitively lays down arms and disbands.
Eta wants an independent Basque homeland made up of the Spanish and French Basque regions and the Spanish region of Navarre.
Spanish media reports say the conference will pass a resolution calling on Eta to "definitively" lay down arms.