President Michael D Higgins has said his thoughts are with the people of Venezuela after the death of Hugo Chavez.
The Venezuelan President died after a two-year battle with cancer, ending the socialist leader's 14-year rule of the South American country. The 58-year-old won a new six-year term as recently as October.
Mr Higgins said: "President Chavez achieved a great deal during his term in office, particularly in the area of social development and poverty reduction."
He continued: "I extend my sincere condolences to the family of President Chavez on their great loss. My thoughts and best wishes are also with the people of Venezuela as they come to terms with this sad news."
The death was announced by Vice President Nicolas Maduro, surrounded by other government officials, in a national television broadcast.
Sinn Fein's Gerry Adams paid tribute to Mr Chavez, who he said had worked tirelessly to improve the lives of Venezuelan citizens.
"He dedicated himself to building a new and radical society in Venezuela," said Mr Adams. "His progressive social and economic changes took millions out of poverty.
"He extended free health care and education for all citizens and his re-election last year with a huge majority was testimony to his vision."
Mr Adams said Mr Chavez was also a hugely influential figure in South America and in world politics.
"He was an energetic and enthusiastic leader and when it was discovered that he had cancer he confronted his illness with the same courage and determination that marked his political life," he added.