Ireland's Green Party, one of the three previous governing parties, may lose a significant number of seats - as attention turns to forming a new coalition.
Counting is still in the early stages, with the first seats filled in the late afternoon. The final result may not be clear for days.
But that hasn't stopped the leaders of Sinn Fein and Fianna Fail speculating about the formulation of the next government.
Mary Lou McDonald told Sky News that "no party has an absolutely straightforward path to government".
The Sinn Fein leader said: "This is going to be complicated, this is going to require dialogue and collaboration."
She said she would hold discussions with other left parties "who are committed to the politics of change and a change of government".
Ms McDonald, who was 162 votes short of the quota to be elected on the first count, added that Sinn Fein has "changed the political landscape here in Ireland, because it's not so long ago that only two parties absolutely dominated government and opposition".
But those two parties, Fianna Fail and Fine Gael, look likely to form another coalition but will fall short of the 88-seat majority needed to govern in the Irish parliament.
The centre-right parties have vowed not to form a government with Sinn Fein, citing substantial differences on policy.
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A coalition is inevitable as no party put forward enough candidates to reach a majority in parliament.
Fianna Fail's leader Micheal Martin, who was elected on the first count, said: "It's very, very early days, but we do see a route to a very strong finish here in this election."
Meanwhile, several high-profile ministers look like they may be in difficulty with Green leader Roderic O'Gorman in with a fight to hold on to his seat. He admitted earlier this morning that his party has "not had a good day".
In 2011, the last time the Greens exited a coalition government, the party lost all six of its TDs (MPs).
The Fianna Fail health minister Stephen Donnelly and the Green media minister Catherine Martin also look to be in trouble.
But alleged crime boss Gerard Hutch appears to be in contention for the fourth seat in Dublin Central - the same constituency as Sinn Fein leader Mary Lou McDonald.
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A Special Criminal Court judge described Mr Hutch, 61, as the patriarchal figurehead of the Hutch criminal organisation and said he had engaged in "serious criminal conduct".
However, Mr Hutch has denied the allegations against him and was found not guilty of the murder of David Byrne, who died after being shot six times at a crowded boxing weigh-in event at a hotel in 2016.
It was one of the first deadly attacks of the Hutch-Kinahan gangland feud.
Meanwhile, Labour and the Social Democrats look set to increase their share of votes in this election.
Holly Cairns, the leader of the Social Democrats who was elected to her county council by one vote in 2019, was unable to vote this time around as she gave birth to a baby girl on polling day.
Counting started across the country at 9am this morning.
Voters in Ireland rank their choices rather than choosing one candidate. Prospective politicians must then reach a quota after rounds of vote counting, which often takes several days. There are between three and five seats up for grabs in each constituency.
(c) Sky News 2024: Ireland election: Several ministers fighting for their seats - as attention turns to forming a coaliti