In a major realignment, Sinn Fein support surged 50% to bring it into joint first place on 22% with Fine Gael and Fianna Fail, the two center-right parties that have dominated Irish politics for a century, according to the poll released on Saturday evening after voting ended.
But Sinn Fein, the former political wing of the Irish Republican Army which has reinvented itself as the country's main left-wing party, is likely to fall behind the other two because it fielded fewer candidates for parliament.
Early counting appeared to back up the exit poll findings.
