The agreement reached by bitter rivals Fianna Fáil and Fine Gael could be rejected on Friday by members of the Green Party, a junior partner
Members of three Irish political parties hoping to form a coalition are voting on whether to approve a deal to govern together.
Fianna Fáil, Fine Gael and the Green Party agreed a programme of government last week, four months after a deadlocked general election result meant none of Ireland’s traditional political alliances secured a parliamentary majority.
But there is speculation that Green Party members will reject the agreement, with many saying they oppose it because of what they consider to be unambitious targets on carbon emissions and housing.
Members of all three parties must support the deal for it to pass.
Fianna Fáil and Fine Gael only require a simple majority, and both parties’ leaders have expressed confidence that the deal will be endorsed, but the Greens have a higher threshold of two-thirds.
The results were expected to be announced on Friday evening.
If approved, Fianna Fáil leader Micheál Martin will be elected Taoiseach — prime minister — on Saturday, replacing Fine Gael’s Leo Varadkar.
The parties agreed to rotate the position of taoiseach between them: Varadkar would become Martin's deputy and have a strong say on economic matters until December 2022, when the roles would be reversed.
Sinn Féin, traditionally a minority party on the opposition benches, performed strongly in February’s general election, winning the most first-preference votes.
But both Fianna Fáil and Fine Gael refused to hold coalition talks with Sinn Féin because of its historic links to the IRA.
If the proposed three-party deal fails, it is possible that Ireland could call a repeat general election later in the year.