The leaders of Spain's Basque region and the central government have resumed official relations after three years.
Mr Ibarretxe (right) said he would not give up his plan for autonomy
Basque leader Juan Jose Ibarretxe met Spanish Prime Minister Jose Luis Rodriguez Zapatero in Madrid on Monday.
After the meeting, Mr Ibarretxe said he was ready to work with the Spanish government towards "closer harmony".
A Basque plan for greater autonomy led to a collapse in relations with Madrid under the government of Mr Zapatero's predecessor, Jose Maria Aznar.
Mr Aznar's Popular Party, ousted by Mr Zapatero's Socialists in the March general elections, had opposed the so-called Ibarretxe plan along with the other main parties.
The plan, still being considered by the Basque parliament, envisages extra powers for the region, including separate courts and representation in organisations such as the European Union.
It will allow Basques the right to determine their sovereignty by referendum.
Mr Ibarretxe told Mr Zapatero on Monday that he would not give up his plan for an autonomous Basque region.
"I am absolutely convinced that if the wish of the Basque society can't be respected, it will be difficult to find solutions," he said.
Spanish minister Jordi Sevilla, who was at the meeting, told local media it had gone very well and he was pleased the Basque leader had indicated his willingness to be part of a joint project.
He also said Mr Ibarretxe was also ready to take an active part in the central government's plans for reform, according to Spanish news agency Efe.