"Next month I'll announce to all political parties the start of a process of dialogue with Eta which will end the violence," Jose Luis Rodriguez Zapatero said.
The Spanish premier was speaking at a meeting of his ruling Socialist party in the Basque town of Barakaldo, near Bilbao in northern Spain.
Talks are expected to focus on issues such as the status of Eta prisoners in Spanish jails.
Basque radicals, however, want a parallel set of talks to deal with longer-term issues such as independence.
Spain's conservative opposition has criticised Zapatero for being willing to deal with Eta while it is still armed, and have accused him of rushing into talks.
"It could be that some people are in a hurry, some might think that this process should never have started but... we must make peace irreversible and produce a Basque country with greater potential than ever," Zapatero said on Sunday.
A recent poll by the government found that many Spaniards remain sceptical of the peace process.
Eta has killed more than 800 people since the late 1960s in its battle for an independent Basque homeland in northern Spain and southwest France.
Its last fatal attack was in 2003, when two police officers were killed by a bomb in Sanguese, northern Spain.